STRUCTURAL COMPARISON OF THE CHORION SURFACE OF 5 PHILONTHUS SPECIES (COLEOPTERA, STAPHYLINIDAE)

Surface structures of eggs of five species of Philonthus are illustrat ed with the aid of scanning electron micrographs. Eggs studied are of the following cow-dung-inhabiting species in northcentral Florida: Phi lonthus longicornis Stephens, P. flavolimbatus Erichson, P. ventralis (Gravenhorst), P. sericans (Gravenhorst) and P. hepaticus Erichson. Th e eggs of P. longicornis, P. flavolimbatus and P. ventralis have high, longitudinal ridges, which are 4-5 for P. ventralis, but 7-8 for the other two species. The ridges of P. longicornis eggs are continuous an d wider, and the egg surface between the ridges is covered by tubercle s, whereas the ridges of P. flavolimbatus eggs are discontinuous (with weak connections between the tubercles) and narrower, and the egg sur face between the ridges is covered by sharp teeth. Eggs of P. sericans have low, parallel and connected ridges, which consist of minute gran ules and scattered enlarged granules over the entire surface. Eggs of P. hepaticus are covered by compact, minute granules and cone-shaped s tructures resembling volcanoes. Aeropyles occur on the egg ridges in P . longicornis and P. flavolimbatus, but on the surface between the rid ges in P. ventralis and P. sericans. A key is given to the five specie s of Philonthus eggs.