12 BURGESS ON THE ANATOMY 



the segment. This is the course of the ovarian tubes before sexual maturity. Each tube 

 contains a line of eggs diminishing in size from base to tip, in corresponding degrees 

 of development. As the eggs increase in size, the tubes become more or less spirally 

 coiled, and fill a large portion of the abdomen. 



In the roof of the large vestibule on the ventral surface of the abdomen between the 

 seventh and eighth segment, already described above, is the opening of the vagina. The 

 vagina (v.) is a curved canal, with horny walls, which opens into a large and very mus- 

 cular organ, the copulatory pouch. This pouch is oblong oval in shape, with a shallow 

 constriction about the middle, the greatest diameter being posterior to the constriction. 

 The walls are very thick and muscular, and the lining of the internal cavity is covered 

 with conical teeth above, and is elsewhere thrown into numerous longitudinal folds or 

 ridges. 



On the upper side of the pouch, and just beyond its beginning, is a small tube opening 

 into it. After two or three convolutions this tube passes a into the oviduct some distance 

 below its fork ; it expands near the middle into a pear-shaped chamber, — the sperm reser- 

 voir or spermatheca {sp.). 



Besides these organs are also a pair of tubular glands, and a single one which discharge 

 into the viaduct, behind the orifice of the sperm duct. They are known as the accessory, 

 or colleterial glands. Each of the paired glands has a curious, twisted, somewhat cornu- 

 copia-shaped dilatation near its orifice ; each gland is about twenty-five mm. long. The 

 single gland is nearly twice as long as the others, and has a corrugated external surface. 

 The three glands lie in coils over the other organs ia the seventh and eighth segments. 

 Their function is supposed to be connected with the formation of the egg shell. 



Male Oegans op Eepkoduction. The internal male organs are very simple in the 

 Lepidoptera; they consist (see pi. 2, fig. 17, natural size), of a single large, globular testis, 

 (t), formed by the consolidation of the two kidney-shaped testes of the larva ; of two 

 efierent ducts {vasa defereniia), v.d.,mto each of which, shortly before their union into the 

 ductus ejacidatorius {d.e.), a single gland (gl.) opens. 



The compound testis lies in the fifth somite, immediately behind the food-reservoir; 

 the intestine passes to the left of it and its ducts, etc., corresponding to the position of 

 the former in the female. It is supported by the tracheae arising from the fifth abdominal 

 spiracles, five branches from which extend to the testis on either side, and on reaching it 

 divide into innumerable minute branchlets, which spread over its surface (see fig. 18). 

 The diameter of the testis is nearly 3 mm. The efierent ducts arise close together on the 

 posterior face of the testis. They are about 30 mm. long, and 0.15 mm. in diameter, to 

 their junction with the glands. As shown in fig. 17, the ducts seem to lead into the 

 glands, and the basal ends of' the latter then continue to the point of union into the ductus 

 ejacidatorius. The glands are tubes about 40 mm. long, and have an average diameter of 

 0.5 mm.; they are somewhat larger at the tip. The portion of the duct between the glands 

 and the ductus ejaculatorius is 10 mm. in length, of the same diameter as the glands, but 

 tapering gradually to the point of junction. The ductus ejacidatoriiis is about 120 mm. 

 long, and slightly stouter than the first division of the eiferent ducts. It ends in a bulb- 

 like expansion (p.h.) at the base of the penis. 



