EGGSHELL FINE-STRUCTURE OF BRADYSIA-APRICA (WINNERTZ) (DIPTERA, SCIARIDAE)

The eggshell fine structure of the dark-winged fungus-gnat Bradysia aprica (Winnertz) (Diptera: Sciaridae) was investigated by scanning and transmission electron microscopy. At the anterior pole of the ovoid egg is a single micropyle, centrally located in a well-defined micropylar area. The latter is covered by many long drumstick-like chorionic processes that are longer and more numerous than those of the rest of the egg surface. Cross-sections of the eggshell show 3 concentric envelopes: the vitelline envelope, wax layer and chorion. The chorion consists of 3 components with different morphological features: the inner, intermediate and outer chorion. The latter 2 layers, involved in the organization of the drumstick-like processes, have homogeneous features, whereas the former is crystalline and resembles the innermost chorionic layer of other Diptora.