CHORIONIC MORPHOLOGY OF EGGS OF THE PSOROPHORA-CONFINNIS COMPLEX IN THE UNITED-STATES - II - PREDEPOSITION AND POSTDEPOSITION STUDIES OF PSOROPHORA-COLUMBIAE (DYAR AND KNAB) EGGS

Scanning and transmission electron microscopic techniques were used to determine the morphology of the exochorion and endochorion of Psoroph ora columbiae eggs as found in the ovary and after deposition. In the ovary, the outer chorionic reticulations and tubercles of the eggs are ornately developed below the follicular epithelium. Expansion of the eggs after deposition causes the outer chorionic reticuli and sculptur ing (i.e., minor and major tubercles) to form the characteristic spino se appearance of Psorophora eggs. Transmission electron microscopic mi crographs of cross and sagittal sections of the chorionic layers of Ps . columbine eggs indicate that the major outer chorionic tubercles hav e 3 distinct regions. The 3rd region was found only on the dorsum of t he tubercle. Elevation of major tubercles appears to be regulated, at least in parr, by ambient moisture conditions, and one function of the se tubercles seems to be adhesion of the egg to an oviposition surface .