平疣桑椹石磺生殖系统结构及精子储存场所

雌雄同体贝类精子的储存和利用规律一直是国内外贝类生物学研究的难点之一,本文利用活体解剖、显微观察、组织切片和扫描电镜技术,综合研究了平疣桑椹石磺(Platevindex mortoni)的生殖系统及精子储存场所。结果显示,其生殖系统包括生殖器本部、雌性生殖部分和雄性生殖部分。生殖器本部由两性腺、两性输送管、蛋白腺、黏液腺、支囊组成;雌性生殖部分包括输卵管、受精囊、阴道,位于身体中后方体腔内;雄性生殖部分包括输精管、刺激器、阴茎、阴茎鞘和阴茎牵引肌,位于身体前端右侧体腔内;其阴茎有阴茎鞘,阴茎表面布满倒刺。平疣桑椹石磺阴茎为直线状,无雄性附属腺。未交配的性成熟个体支囊内充满细长精子,受精囊内无精子;而交配后充当雌性个体的支囊内均为细长的自体精子,受精囊内有大量活力较强的粗短精子,其支囊为自体精子的存储场所,而受精囊为异体精子的存储场所。其精子储运情况为:两性腺内精子成熟后暂存于支囊,交配时通过输精管运输至阴茎,由阴茎输送精子至对方的阴道,异体精子进入受精囊内存储待用。     

Morphology and function of the female reproductive system of Ebalia tumefacta (Decapoda,Brachyura, Leucosiidae)

In this article, the morphology and function of the female reproductive organs of Ebalia tumefacta were investigated using histological methods. While the vagina conforms to the concave type, the study reveals a new orientation of seminal receptacle compartments. The seminal receptacle consists of two chambers, which are oriented in anterior‐posterior direction. This is in contrast to the dorso‐ventral orientation of seminal receptacle chambers in all other known brachyuran crabs. The anterior chamber is lined by cuticle, whereas the posterior chamber is covered with a holocrine glandular epithelium. The oviduct connection is located ventrally, close to the opening of the vagina. The oviduct orifice is characterized by a transition of the epithelium lining of the oviduct to the seminal receptacle holocrine glandular epithelium. Special features are muscle fibers, which are attached to the oviduct orifice and to the sternal cuticle as well. The muscle fibers can be found exactly at that point where the oviduct opens into the seminal receptacle and are secondly attached to the sternum beneath. This musculature is newly described for Eubrachyuran crabs. This musculature can be interpreted as an important feature in the fertilization and egg‐laying process in relation to supporting and controling the inflow of eggs into the seminal receptacle lumen. These new discoveries were compared to the known pattern of an Eubrachyuran seminal receptacle. J. Morphol. 276:517–525, 2015. © 2014 Wiley Periodicals, Inc.     

Biochemistry of seminal secretions of the crab Scylla serrata with reference to sperm metabolism and storage in the female.

Biochemical studies on the male reproductive tissues and seminal secretions have been made with reference to sperm metabolism and different stages of maturity in the crab Scylla serrata. The results reveal that the seminal plasma and spermatophores are rich in protein, carbohydrate, and lipid. In general, organic components of spermatophores are considerably higher than those of seminal plasma. Enzyme studies show that the succinate dehydrogenase (SDH) activity is very low, whereas fumarate reductase (FR) and lactate dehydrogenase (LDH) exhibit high activity. Electrophoretic studies on LDH show that, in addition to the occurrence of a sperm-specific fraction, LDHx, the M-type subunits are predominant in the mature spermatophores. These results from enzyme studies suggest that sperm metabolism is mainly anaerobic, utilizing the carbohydrates as substrates. The results for maturational changes reveal that the male reproductive tissues and their secretions contain lesser quantity of organic components in the immature crabs; as the maturity proceeds, there is not only concentration of organic substances but also an increase in the size of spermatophores. The concentration of biochemical constituents is highest in the proximal vas deferens (PVD), suggesting that the granular seminal plasma as well as the sperm-agglutinating substance and spermatophoric wall are secreted in this region. The spermatheca of the unmated female crabs are poor in organic constituents. After mating, their contents are enriched by organic substances derived from contributions of the seminal substances. During sperm storage in the spermatheca, only the carbohydrates decline steeply. A low activity of SDH, but a moderate level of LDH and a high level of FR activity, is recorded in the spermathecal content of mated crabs, providing further evidence for anaerobic metabolism of sperm during storage in female. A sharp fall in the stored carbohydrates constitutes further evidence in this regard.     

Comparative study of the morphology of the female seminal receptacles of Ilia nucleus and Persephona mediterranea (Decapoda,Brachyura, Leucosiidae)

Because of the poor knowledge of the morphology of the female reproductive organs of most brachyuran crabs, this study investigated two Atlantic representatives of the family Leucosiidae, Ilia nucleus (Linnaeus, 1758) and Persephona mediterranea (Herbst, 1794), using histological methods and magnetic resonance imaging (MRI). While the vagina conforms to the concave type, the arrangement of the two chambers of the seminal receptacle differs strongly from that of other eubrachyuran sperm storage organs. Both chambers are oriented laterally within the crab's body. This is in contrast to the dorso-ventral orientation described in most other known brachyuran crabs. The lateral chamber is covered by cuticle, whereas the medial chamber is covered by a holocrine glandular epithelium. The oviduct connection is located ventrally, posterior to the vagina. The oviduct orifice is characterized by a transition from the epithelium lining the oviduct to the seminal receptacle's holocrine glandular epithelium. Moreover, muscle fibres are attached to the oviduct orifice and to the sternal cuticle. This musculature can be interpreted as an important feature in the fertilization and egg-laying process by supporting and controlling the inflow of eggs into the seminal receptacle lumen. The results of this study are compared to the morphology of the seminal receptacle of another leucosiid crab, Ebalia tumefacta (Montagu, 1808), and to those of other known eubrachyuran crabs.     

Morphology of the female reproductive system of European pea crabs (Crustacea,Decapoda, Brachyura,Pinnotheridae)

Commensal pea crabs inhabiting bivalves have a high reproductive output due to the extension andfecundity of the ovary. We studied the underlying morphology of the female reproductive system in the Pinnotheridae Pinnotheres pisum, Pinnotheres pectunculi and Nepinnotheres pinnotheres using light microscopy and transmission electron microscopy (TEM). Eubrachyura have internal fertilization: the paired vaginas enlarge into storage structures, the spermathecae, which are connected to the ovaries by oviducts. Sperm is stored inside the spermathecae until the oocytes are mature. The oocytes are transported by oviducts into the spermathecae where fertilization takes place. In the investigated pinnotherids, the vagina is of the “concave pattern” (sensu Hartnoll 1968 ): musculature is attached alongside flexible parts of the vagina wall that controls the dimension of its lumen. The genital opening is closed by a muscular mobile operculum. The spermatheca can be divided into two distinct regions by function and morphology. The ventral part includes the connection with vagina and oviduct and is regarded as the zone where fertilization takes place. It is lined with cuticle except where the oviduct enters the spermatheca by the “holocrine transfer tissue.” At ovulation, the oocytes have to pass through this multilayered glandular epithelium performing holocrine secretion. The dorsal part of the spermatheca is considered as the main sperm storage area. It is lined by a highly secretory apocrine glandular epithelium. Thus, two different forms of secretion occur in the spermathecae of pinnotherids. The definite role of secretion in sperm storage and fertilization is not yet resolved, but it is notable that structure and function of spermathecal secretion are more complex in pinnotherids, and probably more efficient, than in other brachyuran crabs. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc.     

Sperm storage and viability in Photinus fireflies

In many species females mate with and store sperm from multiple males, and some female insects have evolved multiple compartments for sperm storage. Sperm storage and sperm viability were investigated in two firefly species, Photinus greeni and P. ignitus, which differ in the morphology of the female reproductive tract. Although the primary spermatheca is similar in both species, P. greeni females have an additional, conspicuous outpocketing within the bursa copulatrix whose potential role in sperm storage was investigated in this study. An assay that distinguishes between live and dead sperm was used to examine sperm viability in male seminal vesicles and sperm storage sites within the female reproductive tract. For both Photinus species, sperm from male seminal vesicles showed significantly higher viability compared to sperm from the primary spermatheca of single mated females. In single mated P. greeni females, sperm taken from the channel outpocketing (secondary spermatheca) showed significantly higher viability compared to sperm from the primary spermatheca. This sperm viability difference was not evident in double mated females. There were no significant differences between P. greeni and P. ignitus females in the viability of sperm from the primary spermatheca. These studies contribute to our understanding of post-mating processes that may influence paternity success, and suggest that sexual conflict over control of fertilizations may occur in multiply mated firefly females.     

Histology of the spermateca and stored sperm of Tenuisvalvae notata (Coleoptera: Coccinellidae)

The predatory ladybird beetle Tenuisvalvae notata (Coleoptera: Coccinellidae) (Mulsant) is a polygamous species and its morphology, as well as the storage capacity of seminal fluid in the spermatheca, may affect its reproductive performance. Thus, the present study evaluates the spermatheca morphology of virgin and mated T. notata females using light and scanning microscopy. The results show that the spermatheca of T. notata is kidney shaped and consists only of the receptacle and spermathecal duct, being morphologically similar in virgin and mated females. There is no secretion in the spermathecae of virgin females and, in mated females, only once it was not possible to observe the presence of spermatozoa. By contrast, females mate multiple times it is possible to observe spermatozoa in the lumen of the spermatheca surrounding the secreted material. Polygamy in T. notata might be related to the maintenance of viable spermatozoa in the spermatheca, in which case the female would prefer to copulate more times during its adult life than to store spermatozoa for a longer period of time.     

Effects of tissue extracts on oviduct contraction in the migratory grasshopper,Melanoplus sanguinipes

The isolated oviduct of the migratory grasshopper, Melanoplus sanguinipes, shows a myogenic, rhythmic pattern of contraction. The pattern of contraction can be modified by treatment with hemolymph or extracts from a variety of tissues from animals of differing age, sex, and mated status. Extracts of oviducts and ventral nerve cord (VNC), as well as hemolymph, from both virgin and mated females were almost always stimulating, though their effect on frequency, amplitude and/or tonus varied. In contrast, whereas extracts of spermatheca and brain from mated females were stimulating, extracts of these tissues from virgin females inhibited contraction. All male material tested (long hyaline tubules (LHT), the male accessory gland complex less the LHT, testes, brain, VNC and hemolymph) stimulated oviduct contraction in a dose-dependent manner, usually enhancing at least two of frequency, amplitude and tonus. However, oviposition-stimulating protein, a purified product of the LHT, provoked only an increase in frequency when applied to the oviduct. LHT extract modulated the effects of virgin female tissue extracts, always in a stimulatory manner.     

Ultrastructural organization of the genital tracts in amphigonic females of Euceraphis betulae Koch (Aphididae: Calaphidinae)

The ultrastructure of the genital tracts in amphigonic females of Aphidoidea is described for the first time, using Euceraphis betulae Koch (Aphididae: Calaphidinae) as a representative. The female reproductive apparatus consists of two ovaries, each one with three/four meroistic telotrophic ovarioles; two sac‐like accessory glands lie laterally to a sac‐like seminal receptacle, opening into the dorso‐medial part of the common oviduct by means of a spermathecal duct. A marked secretory activity takes place in the epithelial cells of all the investigated tracts as shown by ultrastructural observation of many organelles involved in this process. No evident golgian area was observed in the cytoplasm of these cells. Extensive smooth endoplasmic reticulum, whose probable role is here discussed, was observed in epithelial cells of the wall of the accessory gland. Spermathecal duct and seminal receptacle had peculiar features that could be related to different secretory activities carried out by these two parts of the spermatheca.     

Ultrastructural and functional aspects of the spermatheca in the American harlequin bug, Murgantia histrionica (Hemiptera: Pentatomidae)

The spermatheca of Murgantia histrionica (Hahn) was investigated using fluorescence, scanning and transmission electron microscopy. The aim of the study was to elucidate the structure of this organ, pointing out differences between mated and unmated females. Results have shown an elaborated cuticular structure associated with muscular and glandular tissues. The spermatheca is joined with the common oviduct by the spermathecal duct, forming a thin saccular dilation through two consecutive invaginations. The distal part of the organ is formed by a series of two communicating cuticular chambers. The first cylindrical-shaped chamber, corresponding to the coiled region, is wrapped by longitudinal muscular fibers suspended between two cuticular flanges. The contractions of these fibers compress a deformable zone of the cylinder, pumping the sperm toward the spermathecal duct. Without contractions the cylinder results to be isolated from the proximal part of the spermatheca by means of a valve. The second chamber, corresponding to the spermatheca, is made of two parts: a truncated-conical sub chamber, with a constant cuticular thickness, bearing on itself the distal flange, where muscular fibers are attached. The second part is a bulb-like structure wrapped in a glandular epithelium. The secretory units are composed by two cells: a secretory cell and an associated duct cell. Every evacuating duct shows a little reservoir just after the terminal apparatus, and converge inside the distal bulb after a tortuous path. The functional implications of this structure in the reproductive biology of M. histrionica are discussed.     

斑衣蜡蝉雌性生殖系统超微结构

【目的】明确斑衣蜡蝉Lycorma delicatula雌成虫生殖系统整体形态及超微结构特征,为蜡蝉总科昆虫分类及系统发育探讨提供更多形态学证据。【方法】采用光学显微镜与透射电子显微镜,观察斑衣蜡蝉雌成虫生殖系统整体形态和各主要器官的超微结构。【结果】斑衣蜡蝉雌成虫生殖系统主要包括1对卵巢、1个中输卵管、1个交配囊、1个交配囊管、1个前阴道、1个后阴道、1个受精囊、1个受精管和2根受精囊附腺。卵巢为端滋式,由14根卵巢小管组成,卵室由固有膜、滤泡细胞和卵细胞组成,卵巢小管中的滋养细胞清晰可见;中输卵管位于前阴道基部,由中输卵管腔、上皮细胞、肌肉鞘和基膜组成;交配囊膨大呈圆球状,囊壁由上皮细胞、肌肉层和基膜组成;交配囊管呈圆柱状,连接交配囊和后阴道,由肌肉鞘、上皮细胞层和管腔组成;前、后阴道超微结构相似,主要由肌肉鞘、基膜、上皮细胞和管腔组成,但后阴道上皮细胞细胞核周围存在分泌颗粒,且管腔内有大量微绒毛,而前阴道壁内包含有大量囊泡结构;受精管从中输卵管末端延伸至受精囊,由基膜、厚层肌肉鞘和管腔组成;受精囊为受精管近末端略膨大的囊状结构,由肌肉鞘、基膜、上皮细胞和囊腔构成;雌性受精囊附腺着生于受精囊末端,为均匀的螺旋管状,主要由肌肉层、上皮细胞层和附腺中心管腔组成。【结论】斑衣蜡蝉雌性生殖系统与已报道的蜡蝉总科其他类群的雌性生殖系统结构相似,但卵巢小管数目有差异;蝉亚目中不同总科雌成虫雌性附腺与受精囊附腺的形态特征存在明显区别;斑衣蜡蝉雌性生殖系统超微结构与叶蝉总科和沫蝉总科昆虫也存在部分差异。这些差异是否可以作为头喙亚目高级阶元的划分依据仍有待于进一步研究。     

宽翅曲背蝗受精囊形态与超微结构观察

[目的]明确宽翅曲背蝗Pararcyptera microptera meridionalis雌虫受精囊的形态、组织结构与超微结构,为更好地认识昆虫受精囊的功能提供依据.[方法]本研究以宽翅曲背蝗已交配雌成虫为实验材料,利用光学显微镜和透射电子显微镜观察其受精囊的形态、组织结构和超微结构.[结果]宽翅曲背蝗受精囊由一个端囊和一条长的受精囊管组成,端囊用于储存精子.端囊和受精囊管有相似的组织学结构,由外到内依次为肌肉层、基膜、上皮层及表皮内膜.上皮层含上皮细胞、腺细胞和导管细胞3种细胞类型.腺细胞具有一个被有微绒毛的细胞外腔.腺细胞的分泌物经细胞外腔通过分泌导管进入到受精囊腔.分泌导管由导管细胞形成.[结论]在宽翅曲背蝗受精囊的端囊和受精囊管上,内膜和腺细胞的细胞外腔结构均存在差异,由此推测,端囊和受精囊管的功能存在一定差异.上皮细胞的超微结构特点显示上皮细胞具有支持、分泌和吸收的功能.     

Male reproductive system of the arrow crab Stenorhynchus seticornis (Inachoididae)

Our aim was to describe the reproductive system of males and the formation of sperm packages in the seminal receptacle (SR) of recently mated females of the arrow crab Stenorhynchus seticornis. The male reproductive system was analyzed, and was described using light microscopy and histological and histochemical methods. The first pair of gonopods was described by means of scanning electron microscopy. Additionally, the dehiscence of spermatophores was tested using samples obtained from the vas deferens of males and from the seminal receptacle of recently mated females. Testes were tubular type, and each vas deferens consisted of three regions: the anterior vas deferens (AVD), including a proximal portion that was filled with free spermatozoa and a distal portion contained developing spermatophores; the median vas deferens (MVD) that contained completely formed spermatophores; and the posterior vas deferens (PVD), which contained only granular secretions. The accessory gland, which was filled with secretions, was located in the transition region between the MVD and the PVD. The spermatophores from the MVD were of different sizes, and none of them showed dehiscence in seawater, whereas those spermatophores in contact with the seminal receptacle were immediately broken. The ultrastructure of the gonopods revealed the presence of denticles at the distal portion, which contribute to the mechanical rupture of the spermatophore wall during the transfer of sperm. The contents of the PVD and accessory gland of males are transferred together with the spermatophores, and are responsible for the secretions observed among the sperm packets in the SR of the female. We suggest that these secretions formed the layers found in the SR of recently mated females, and may play a role in sperm competition in arrow crabs.     

A hypothesis about the origin of sperm storage in the Eubrachyura, the effects of seminal receptacle structure on mating strategies and the evolution of crab diversity: How did a race to be first become a race to be last?

The origins and evolution of sperm storage in Brachyura are enigmatic: sperm is either stored in seminal receptacles, accessible via the vulvae on the sixth thoracic sternite, or in spermathecae at the border between the seventh and eighth sternites. Crabs with spermathecae are collectively referred to as “podotremes” while crabs with seminal receptacles belong to the Eubrachyura. The position of gonopores is the primary basis for subdividing the Eurachyura into the Heterotremata (female vulvae + males with coxal gonopores) and Thoracotremata (female vulvae + males with sternal gonopores). We present a hypothesis about the evolution of seminal receptacles in eubrachyuran female crabs and argue that the sternal gonopore has been internalized into chitin-lined seminal receptacles and the vulva is in fact a secondary aperture. The loss of some or all of the ancestral chitinous seminal receptacle lining was linked to ventral migration of the oviduct connection. Male and female strategies are to maximize gamete fertilization. The most important variable for females is sperm supply, enhanced by long-term storage made possible by the seminal receptacle. To maximize their fertilization rates males must adapt to the structure of the seminal receptacle to ensure that their sperm are close to the oviduct entrance. The major evolutionary impetus for female mating strategies was derived from the consequences of better sperm conservation and the structure of the seminal receptacle. The advantages were all to the females because their promiscuity and sperm storage allowed them to produce more genetically variable offspring, thereby enhancing variation upon which natural selection could act. We extend our arguments to Brachyura as a whole and offer a unifying explanation of the evolution of seminal receptacles, comparing them with the spermathecae found in “Podotremata”: they were independent solutions to the same problem: maintaining sperm supply during evolutionary carcinization.Explanation of eubrachyuran mating strategies requires analysis of the mating–moulting link, indeterminate vs. determinate growth format and seminal receptacle structure. Two alternatives for each of these characters means that there are eight possible outcomes. Six of these outcomes have been realized, which we term Portunoid, Majoid, Eriphoid, Xanthoid, Cancroid, and Grapsoid–Ocypodoid strategies, respectively. Mapping these characters on to a workable phylogeny (wherein some changes to the seminal receptacle + moulting–mating links are assumed to have occurred more than once) produces the following relationships: Portunoids + Majoids are a sister group to the rest of the Eubrachyura, which fall into two sister groups, Eriphoids + Xanthoids and Cancroids + Grapsoid–Ocypodoids and the “Podotremata” is sister group to all the Eubrachyura. We conclude that what began as a race to be the first to mate was turned on its head to become a race to be last, by the evolutionary changes to the seminal receptacle. Eubrachyuran females were advantaged by greater reproductive autonomy, more opportunity to mate with other males, resulting in more genetically variable progeny and leading to the evolution of much greater taxonomic diversity compared to “podotremes”.     

Morphological analysis of the female reproductive system of Stenorhynchus seticornis (Brachyura: Inachoididae) and comparisons with other Majoidea

We examined the female reproductive system of the yellowline arrow crab Stenorhynchus seticornis by means of histological and histochemical techniques. Mature specimens obtained in the field were kept in the laboratory for mating experiments. After 24 h, newly mated females were dissected, and their reproductive trait routinely processed for embedding in historesin. The specimens examined each possessed a pair of kidney‐shaped seminal receptacles (SR), and these we classified as ventral type, based on the location of the oviduct opening. The mesodermal dorsal region (DR) of SR consisted of a stratified epithelium with scaly cells, while the ectodermal ventral region (VR) was composed of a simple epithelium covered by a cuticle. The oviduct opened at the transition region (TR) between DR and VR and had no velum. The simple epithelium of TR had more folds on the face of the oviduct opening. The vagina exhibited the same features as the TR epithelium and was contiguous to VR, anchored by muscles. In the lumen, from one to three strata of sperm packets were observed, the dorsal one containing free sperm, and the most ventral stratum, spermatophores. An acidophilic glycoprotein layer enclosed the strata. Spermatophores in the ventral stratum were enclosed in a voluminous secretion, composed by acid polysaccharides most likely from the last male mated. The ventral‐type receptacle, stratified sperm packets, and polyandry, usually observed in females of Majoidea, suggest the occurrence of sperm competition in S. seticornis, favoring the sperm of the last male mated, as its sperm mass is located near the opening of the female oviduct.     

Mating behavior,insemination and sperm transfer in the ground beetle Carabus insulicola

Mating behavior and the processes of insemination and sperm transfer in the ground beetle Carabus insulicola were analyzed. C. insulicola has elaborate genitalia, in which the strongly sclerotized male copulatory piece is inserted into the female vaginal appendix in copula. During mating, I observed pre-copulatory struggles of males and females, as well as delays in ejaculation, suggesting the presence of intersexual conflicts. Insemination was achieved with a spermatophore, which strongly adhered to the openings of the spermatheca, common oviduct, and vaginal appendix. The spermatophore dissolved after copulation, and sperm were transferred into the spermatheca within three hours after copulation. Sperm bundles were contained within the testes and spermatophores, but free spermatozoa were found in the spermatheca.     

Pattern of sperm storage and migration in the reproductive tract of the swallowtail butterfly Papilio xuthus: cryptic female choice after second mating

Females of the swallowtail butterfly Papilio xuthus L. (Lepidoptera: Papilionidae) mate multiply during their life span and use the spermatophores transferred to increase their longevity as well as fecundity. Sperm from different males may be stored in the sperm storage organs (bursa copulatrix and spermatheca). To clarify the pattern of sperm storage and migration in the reproductive tract, mated females are dissected after various intervals subsequent to the first mating, and the type and activity of sperm in the spermatheca are observed. When virgin females are mated with virgin males, the females store sperm in the spermatheca for more than 10 days. Sperm displacement is found in females that are remated 7 days after the first mating. Immediately after remating, these females flush out the sperm of the first male from the spermatheca before sperm migration of the second male has started. However, females receiving a small spermatophore at the second mating show little sperm displacement, and the sperm derived from the small spermatophore might not be able to enter the spermatheca. Females appear to use spermatophore size to monitor male quality.     

Ultrastructural studies on the nematode Xiphinema diversicaudatum: Egg shell formation

The ultrastructure of the formation of the egg shell in the longidorid nematode Xiphinema diversicaudatum is described. Upon fertilization a vitelline membrane, which constitutes the vitelline layer of the egg shell, is formed. The chitinous layer is secreted in the perivitelline space, between the vitelline layer and the egg cell membrane. On completion of the chitinous layer, the material of the lipid layer is extruded from the egg cytoplasm to the outer surface, through finger-like projections. Both chitinous and lipid layers are secreted by granules in the egg cytoplasm that disappear as the layers are completed. Chitinous and lipid layers are formed during the passage of the egg through the oviduct. The vitelline layer is enriched with secretions produced by the oviduct cells and then by phospholipids secreted by the cells of the pars dilatata oviductus. The inner uterine layer is also formed by deposition of secretory products apposed on the egg shell in the distal uterine region and Z-differentiation. In the proximal part of the uterus, the egg has a discontinuous electron-dense layer, the external uterine layer. Tangential sections between chitinous and uterine layers revealed the presence of holes, possibly egg pores, delimited by the two uterine layers.