188 Prof. E. K. Brandt on the Anatomy of 



cavities or air-vessels are not yet tracheee. In this respect 

 the Sesiidffi differ much from the Sphingidse, in which they 

 are placed together in one cluster in front, and in which such 

 vesicles or sacs are absent in the transverse branches of the 

 trachese on the ventral surface. 



The male sexual apparatus of S. tipuliformis consists of the 

 following parts : — (1) the testes, (2) the deferent ducts, (3) 

 the vesicuke seminales, (4) the ductus ejaculatorius, (5) the 

 penis, (6) the accessory glands. 



The testes, as is invariably the case in Lepidoptera, are two 

 in number, and are enclosed in a common sac or scrotum. 

 The deferent ducts are short and broad, opening into the 

 vesiculce seminales, which are small oblong sacs. The ductus 

 ejaculatorius is a long sinuous tube. The penis is horny, 

 with a guitar-shaped depression in the middle. The accessory 

 glands are long and very sinuous. 



The female sexual apparatus of S. tipuliformis consists of 

 the following parts : — (1) the two ovaries, (2) the oviduct, 

 (3) the vagina, (4) two accessory glands, (5) receptaculum 

 semim's, (6) unpaired accessory gland, (7) copulatory pouch, 

 and (8) ovipositor. 



While investigating the anatomy of Sesia scoliceformis I 

 noted a remarkable peculiarity in the structure of the ovaries. 

 Each ovary contains fourteen tubes, each of which emits a 

 small excretory canal. Every two canals unite, forming- 

 seven egg-tubes, which then combine to form one oviduct on 

 each side, and afterwards unite at the vagina. This pecu- 

 liarity in the structure of the ovaries is very remarkable and 

 constitutes an exception to their usual type in Lepidoptera. 

 In all other Lepidoptera hitherto examined there are only 

 four egg-tubes in each ovary. It would be very interesting 

 to discover whether the same anomaly in the structure of the 

 ovaries is to be met with in other species of Sesia, or whether 

 it is peculiar to S. scoliaforniis. On dissecting 8. tipuli- 

 formis 1 found that it exhibited the normal structure of the 

 ovaries. I only count four egg-tubes in each ovary. These 

 ducts are long, rather narrow, and only slightly constricted, 

 so that they form straight rather than undulating tubes. 

 The short broad oviducts open into the long vagina, which is 

 considerably dilated at the end. There are two accessory 

 glands, each of which is constructed of a broad pear-shaped 

 part, opening into the vagina, and a long narrow tube, coiled 

 in the peritoneal cavity. The unpaired supplementary gland 

 consists of a long, narrow, stalk-like tube, opening at the 

 lower end of the vagina. The receptaculum seminis is a long 

 narrow tube, with the rounded end coiled in the cavity of the 



