INTERNAL ANATOMY OF TITE MOTH. 
55 
point is still unsolved. Since the organ is not for sucking, as long sup- 
posed, and is evidently not digestive, it seems likely, or at least pos- 
sible, that it serves simply as a reservoir. It is first developed in the 
pupal stage. 
In a lateral view, as in Fig. 2, the neck of the reservoir is concealed 
by the anterior end of the stomach, which projects into two short lobes 
on each side of the neck. 
The stomach, rf, is very much smaller than in the larva, for it barely 
extends through four abdominal segments. Its walls have the same 
two muscular coats as we have described in the larval stomach, vide 
fftcpro, and the epithelial lining is thrown up into beautiful glandular 
corrugations. The stomach is overlaid with the convoluted malpighian 
ve>>( Is, six in number, three of which, on each side, unite and 
open by a short, common duct into the posterior end of the stomach. 
At the end of the stomach begin? the peculiarly coiled small intestine, 
i, which passes to the left of the bursa copulatrix in the female, and of 
the genitalia in the male. The intestine passes into the wide terminal 
division, or rectum, R, from the front end of which runs out a curved 
blind pouch or caecum, c. In Danais the terminal division is clearly 
separated into an anterior part or colon, and a posterior part, or true 
rectum, but the rectal region is less noticeable in Aletia. 
The course of the aorta, or anterior extension of the heart, in lepi- 
doptera, was not correctly described by the older authors. Burgess ob- 
served its strange bend in the butterflies, and has since studied it in 
several forms of lepidoptera, and published his results in a short paper.* 
In this article he describes and figures the course of the thoracic aorta 
in a noctuid. In Aletia it enters from the abdomen behind, bends im- 
mediately upwards, widens rapidly, makes a slight crook, and then, 
leaching the dorsal wall of the metathorax, to which it is secured by 
fibrous tissue, it makes a sharp bend and runs back upon its own course; 
next curves forwards, and, growing gradually narrower, runs along just 
above the oesophagus into the head, passing with the former through 
the brain. 
The nervous system consists of a chain of ganglia and the nerves. 
The supra-cesophageal ganglion, or brain, occupies nearly the center of 
the head (Plate VII, Fig. 2, Br.), and is connected by very thick commis- 
sures with the sub-u\sophageal ganglion, which passes gradually into 
the cord that leads to the first thoracic ganglion. This is quite distinct, 
but the second and third are almost completely fused, and connect with 
the abdominal gauglia by a very long commissure. In the abdomen 
(Plate VIII, Fig. 2) there are four nerve centers (a.g., a.g.), as is almost 
always the case in the Lepidoptera, lying in the third, fourth, fifth, and 
sixth segments respectively. The last is the largest, and is compounded 
of two or more ganglia fused together; the principal nerves arising from 
it seem to innervate the organs of reproduction. 
* Burgess. E. Proceedings Bost. Soc. Nat. Hist., XXI, 153-156. 
