EGGSHELL ULTRASTRUCTURE IN ONYCHOGOMPHUS-FORCIPATUS-UNGUICULATUS (VANDERLINDEN) (ODONATA, GOMPHIDAE)

The eggshell ultrastructure of the exophytic riverine dragonfly Onycho gomphus forcipatus unguiculatus (Odonata:Gomphidae) is presented using transmission electron microscopy. A homogeneous vitelline envelope is surrounded by a thick, many-layered endochorion and a relatively thic k, homogeneous exochorion. The micropylar projection is covered by a j elly-layer. The structure of the shell is intermediate between known e ndophytic and exophytic eggshells in the order. A possible evolution o f jelly-covered exophytic eggs from endophytic riverine ancestors is d iscussed.