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Quarterly Journal of Microscopical Science, Vol s2-76, 35-61, Copyright © 1934 by Company of Biologists
1 University Scholar of the Government of the Punjab; Department of Zoology, Cambridge
A general account of the internal reproductive organs and the external genitalia and their development is given.
The ‘penis lobes’ develop earlier than the ‘valvae lobes’, and independently of them.
The tegumen is the modified ninth tergite. The tenth segment is visibly distinguished into a tergal and sternal part in the pupal stages, and the anal tube passes between the two sclerites. The uncus and the gnathos are dorsal and ventral processes respectively of the tenth segment. The anellus lobes develop as lateral processes of the ninth sternite on either side of the penis.
The vasa deferentia during larval life do not extend beyond the eighth abdominal segment and lie in a latero-ventral position. They meet the extensions from the ectodermal ‘ductus ejaculatorius duplex’ during the last larval stadium.
From the earliest caterpillar stage there exists a pair of ectodermal ducts formed by the differentiation of the epidermis on the ninth sternite. Towards the end of larval life they divide by constriction to form the accessory glands and the ‘ductus ejaculatory duplex’. At this stage they extend on either side to meet the vasa deferentia.
The vesiculae seminales develop by distension from the region of junction between the vasa deferentia and the proximal portion of the ejaculatory duct.
The ‘ductus ejaculatorius simplex’ arises as an ectodermal invagination between the pair of ‘penis lobes’ during the final larval instar.
It is established that, with the exception of the vasa deferentia, all the remaining elements in the efferent genital system are derived from the ectoderm.
