Revision of Comesomatidae (Nematoda)

The gross and fine morphology of the family Comesomatidae is reviewed and the systematic position of its members revised. Significant differentiating characters of the Comesomatidae within the Chromadorida are: a copulatory apparatus provided with apophyses, a female reproductive system with outstretched ovaries, the presence of marginal tubes within the oesophagus, and a non-sclerotized and enlarged tail tip. For classification within the family the following three main characters are used: the structure of the buccal cavity, the structure of the copulatory apparatus, and the arrangement of the cephalic sense organs. Structure of the Sabatieria type is considered basic. The genera are rearranged in three subfamilies as follows: Sabatieriinae ( Cervonema, Laimelia, Pierrickia, Sabatieria (syn. Actarjania), Scholpaniella ), Dorylaimopsinae (Dorylaimopsis (syn. Mesonchium), Hopperia, Metasabatieria, Paramesonchium, Vasostoma ), Comesomatinae ( Comesoma, Metacomesoma, Paracomesoma. ) Six species of Comesomatidae are described from the øresund, Denmark: Cervonema macramphis sp.n.; Laimelia filipjevi nom. nov. (syn. Sabatieria longicaudata Filipjev, 1922); Sabatieria hilarula De Man, 1922; S. ornata (Ditlevsen, 1918); S. punctata (Kreis, 1924); Dorylaimopsis punctata Ditlevsen, 1918. Representatives of these species constitute more than 40% of the total number of nematodes in the region.     

Variation in density of cattle-visiting muscid flies between Danish inland pastures

Abstract. The density of cattle-visiting flies (Muscidae) and the load of black-flies (Simulium spp.) were estimated in twelve and eighteen inland pastures in Denmark in 1984 and 1985 respectively. No differences in the geographical distribution pattern of the predominant cattle-visiting Muscidae were recorded, whilst the relative abundance and density of the species and the total fly-load varied considerably between pastures. In most cases the mean loads of Haema-tobia irritans (L.) and Hydrotaea irritans (Fall.) on heifers varied significantly in relation to site topography and shelter. These crude site variables explained 65–98% of the variation in densities of horn flies and sheep head flies observed between pastures. Highest densities of Hydrotaea irritans were primarily associated with permanent, low-lying, fairly sheltered grassland sites, whereas the density was low in temporary, dry, wind-exposed pastures. A comparable relationship was found for Haematobia irritans. With Haematobosca stimulans (Mg.) and Morellia spp. no relation between grassland environment and fly density was detected.