Morphology and ultrastructure of the cephalic vesicles in two species of the Gonatopus genus: Gonatopus camelinus Kieffer and Gonatopos clavipes (Thunberg) (Hymenoptera, Dryinidae, Gonatopodinae)

The cephalic vesicles of the immature endo-ectoparasitic larvae of Gonatopus camelinus Kieffer and Gonatopus clavipes (Thunberg)were studied using light and elecronic microscopy. The vesicles appear as hollow evaginations of the cephalic body wall and their tegument consists of a monolayered epithelium externally surrounded by a permeable cuticle. In the first larval instars, the epithelial cells are pyramid-shaped and separated by large intercellular spaces. In the last larval instars they are polyhedral and the intercellular spaces are no longer evident.The vesicles have no connection with the gut of iether the host or the larva. These data suggest that nutrients are absoebed by the dryinid larva from haemolymph of the host through the permeable surface of the cephalic vesicles, where they are stored in the lumen and enter the larval haemolymph without passing through the gut. In all immature larval instars the mouth is closed