FINE-STRUCTURE OF THE EGG ENVELOPES IN LISTRONOTUS-OREGONENSIS (LECONTE) (COLEOPTERA, CURCULIONIDAE) AND MORPHOLOGICAL ADAPTATIONS TO OVIPOSITION SITES

The chronology of the development of the egg chorion of Listronotus or egonensis (Coleoptera: Curculionidae) was studied using transmission a nd scanning electronic microscopy. The exochorion is uniformly covered with tubercles that reduce surface contact with plant sap. These stru ctures could also function as a physical gill. The endochorion is thin and the vitelline membrane, at first granular, changed after oviposit ion to a lamellar structure. The serosal cuticle continued development until about 72 hr after oviposition, at which time it comprised 90 la yers.