Ultrastructural description of the corpora allata of Pimpla turionellae L. (Hymenoptera: Ichneumonidae)

The corpora allata, are endocrine glands which produced juvenile hormone. In this study, corpora allata of adult females of Pimpla turionellae were examined ultrastructurally by using the transmission electron microscopy. The gland is surrounded with thick fibrous capsule that penetrates into the gland as a stromatal ramification. The ultrastructure of gland cells had the same characteristic of protein-secreting cells. These cells had oval shaped nuclei, numerous granules, lysosomes, mitochondria and vacuoles. There are granules of electron-dense, electron-modarate and electron-lucent. These granules are actually membrane-limited secretory vesicles which are filled with the proteinaceous hormone produced by the gland cells. Microtubules and mitochondria were observed in the cytoplasm of axons of neurosecretory cells found among the gland cells.