Int. J. lnsectMorphol. & Embryol., Vol. 17, No. 4/5, pp. 345 357, 1988 (1020 7322/88$3.00+ .(J0 Printedin Great Britain © 1988PergamonPressplc FINE STRUCTURE OF THE FEMALE SEX PHEROMONE-PRODUCING GLANDS IN SESAMIA NONAGRIOIDES LEF. (LEPIDOPTERA • NOCTUIDAE) ISABELLE SRENG and LEAM SRENG Laboratoire de Zoologie, UA 674 CNRS, Universit6 de Bourgogne, 6, Boulevard Gabriel, 21100 Dijon, France (Accepted 5 May 1988) Abstract--The morphology and cytology of the female sex pheromone-producing glands of Sesamia nonagrioides (Lepidoptera : Noctuidae) consist of modified intersegmental membranes; they are unusual compared with those described in other moths. There are 2 different glandular areas (a ventral area, GI, around the ostium bursae and a ring-shaped area, GII, around the ovipositor), instead of a single area (between segments 8 and 9 + 10) as in most other species. Ultrastructural features, such as developed basal invaginations and dilated intercellular spaces indicate transport of material from the hemolymph to the glandular cells, while the presence of abundant mitochondria, numerous free ribosomes, rough endoplasmic reticulum, and inclusions reveal high cellular activity. The smooth endoplasmic reticulum is absent in S. nonagrioides, in contrast to its extensive development in glands producing similar compounds in other moths. The cuticle, abnormally thick (7-8 times thicker than the glandular epithelium), is traversed by dilated pore canals forming cuticular gaps, connected with epicuticular canals. Tl~is system allows the storage and the passage of pheromone in and through the cuticle. Index descriptors (in addition to those in title): Moth, gland cells, exocrine gland, scanning electron microscopy. INTRODUCTION SESAMIA NONAGRIOIDES caterpillars are serious pests of corn in the Mediterranean area: south and south-west France, north-west Italy, Spain and north Africa. Among nocturnal Lepidoptera, the 2 sexes generally come together by aerial odour trails (emission of a sex pheromone). The female S. nonagrioides adopts the typical "calling" posture, during the last 2 hr of scotophase, by extruding her abdominal extremity and secreting the sex pheromone. We have studied the chemical composition of the glandular secretions and have identified some compounds, of which Z-11 hexadecenyl acetate (Zll HDA) and Z-11 hexadecen-l-ol are active in the male sexual behavior. The sexual attractant, a blend of Zll HDA + Z11 HDol in a ratio of 90 : 10, has been tested in the field and found to be competitive with virgin females. For sex pheromone analysis, it is necessary to know the exact production site of the components. Sex pheromone glands of female Lepidoptera generally consist of a modified 345