Morphology and histology of the spermathecal sac, a novel structure in thefemale reproductive system of Therevidae (Diptera : Asiloidea)

The reproductive system of many female Therevidae has a sac-like structure associated with the spermathecae. This structure, termed the spermathecal s ac, has not been recorded previously from any other Diptera and appears uni que to certain members of the Therevidae. There is enormous variety in sper mathecal sac size and shape, with greatest development in the Australasian Therevidae. A histological examination of the reproductive system of two;Au stralian therevids, Agapophytus albobasalis Mann and Ectinorhynchus variabi lis (Macquart) (Diptera: Asiloidea), reveals that the spermathecal sacs are cuticle-lined and that the intima is frequently highly folded. In some mat ed individuals, sperm was found within the spermathecal sac, suggesting tha t sperm and perhaps male accessory gland material is deposited there during copulation. (C) 2000 Elsevier Science Ltd. All rights reserved.