Ultrastructure of the chorion of Dioctria flavipennis Meigen, 1820 (Diptera: Asilidae: Stenopogoninae) compared with those of fourteen asilid species from the mid-Atlantic region of North America

The fine structure of egg morphology of Dioctria flavipennis Meigen 1820 was studied utilizing both scanning electron (SEM) and transmission (TEM) microscopy. Eggs from Aksaray, Turkey, averaged 0.4 mm in length and 0.3 mm in width and had a single micropylar opening at one end. Chorions were covered with small and large circular elevated structures. A micropylar region eclosion groove is reported for the first time. Sperm flagella were present in the micropylar region of some eggs. The endochorion and exochorion were distinguished from each other in TEM micrographs, the former being slighter more dense than the latter. Lamellar sheets, minute canals, and air ducts were also found. Additionally, the exochorion of the egg of D. flavipennis Was compared with those (SEMs) of 14 asilid species from the mid-Atlantic region of North America: Atomosia pitella (Wiedemann), Cerotainia albipilosa Curran, Eudioctria tibialis (Banks), Holcocephala abdoininalis (Say), H. calva (Loew), Laphria divisor (Banks), L. flavicollis Say, L. ithypgi McAtee, L. sicula McAtee, L. virginica (Banks), Leptogaster flavipes Loew, Psilonyx annulatus (Say), Tipulogaster glabrata (Wiedemann), and Tolmerus sp. Brief comments about the phylogeny of the egg chorion and its adaptation to various enviromental conditions are included. Egg morphology may be useful to elucidate taxonomic and phylogenetic relationships among asilids.