296 
PSTOCRE. 
7. THE PUPA OF HAMADRYAS IO, OF EUROPE. 
system. In general the 
abdomen seem to be 
Muscular 
muscles of the 
situated much as in the larva, but are- 
more compact and almost or altogether 
longitudinal, the oblique muscles dis- 
appearing. Those of the under 
face of the abdomen consist, on each 
side of the body, of a ribbon, one milli- 
metre broad, composed of two contiguous 
strips, the outer slightly the broader, 
running next the integument through the 
entire length of the abdomen, the inner 
edge at one millimetre’s distance from 
the nervous cord. 
Digestive system. ‘The oesophagus is 
a slender, thread-like tube, less than 0.1 
mm. in diameter; as it enters the abdo- 
men it is at once directed upward and 
suddenly expands into a small bulbous 
muscular crop, the upper part of which 
opens into the reservoir, a subfusiform 
blind sac, broadly rounded at tip, 1.5 
mm. in breadth and 5 mm. long, reach- 
ing the extremity of the fourth abdom- 
inal segment; immediately on the apical 
contraction of the crop, the stomach 
arises; this is at once many times 
broader than the crop, and remains 
nearly of this size. to the tip of the fourth 
abdominal segment (or where the reser- 
voir ends) ; from this point on it is only 
half its former diameter and extends as 
a straight tube to the middle of the fifth 
abdominal segment. On each side, at 
the base, the stomach bears some rounded 
lobes, nearly as large as the crop, and 
besides these, arranged in a row down 
each side of the median line, it is pro- 
fusely covered with small pea-like 
sur- 
pockets. The intestine is tortuous, of 
considerable length, 0.15-0.18 mm. in 
diameter, and ends in the colon, a blad- 
der-like sac, pyriform in shape and 
about 0.8 mm. long, containing a whitish 
substance: this opens into the rectum, 
a broad and straight tube, 1.5 mm. long 
and 0.25 mm. broad. 
The salivary glands are composed of 
threads about 85 mm. long, and of a uni- 
form size throughout; they first run 
straight beside the slender oesophagus, 
until near the middle of the mesothorax, 
when they become very strongly crinkled, 
forming by their convolutions a fusiform 
mass, 3.25 mm. long and 0.5 mm. broad, 
continuing in the same course to the 
middle of the metathorax. 
The malpighian vessels arise at the ex- 
tremity of the smaller part of the stomach, 
without the intervention of any basal 
sac, three branches arising together 
at the a very short distance from the 
base of their common stem and parting 
from it at right angles. 
Respiratory system. The tracheae 
seem to be much as in the larva, only 
greatly reduced in size, very deli- 
cate, not at all opaque, and not divided 
into two sorts; the lateral longitudinal 
canal of the abdomen appears to be 
larger than any of the other vessels. 
Circulatory system. The dorsal vessel 
is a slender, equal canal, terminating 
abruptly behind at the tip of the fourth 
abdominal segment, lying next the in- 
tegument of the future imago and about 
0.15 mm. in diameter in the abdomen ; 
as it enters the thorax from behind it 
