YorMes—Larva of Platyphylax Designatus. 113 
ing to the beginning of the next division, the mid-intestine. 
The posterior part of the fore-gut seems to function as a sort 
of crop, as it is frequently seen somewhat swollen with food 
when it assumes a rounded outline. (Fig. 1.) 
The mid-intestine, as may be expected from the herbivorous 
habit of the larva, is very large when normally tilled with food. 
It begins with an abrupt enlargement of the alimentary tract 
at the posterior border of the metathorax. The fore gut ap¬ 
parently is telescoped into this. The width of the mid-intes¬ 
tine at this point is more than one-half that of the average ab¬ 
dominal segment. From here to the posterior end, in the mid¬ 
dle of the sixth segment, it tapers gradually to less than one- 
third the width of the abdomen. The end of the mid-intestine 
is marked on its external surface by the attachment of the Mal¬ 
pighian tubules, which are six in number. These tubules ex¬ 
tend anteriorly to the first abdominal segment; they then turn 
back on themselves, extending posteriorly to the eighth segment, 
when they again turn forward and end in the sixth or seventh 
segment after forming several loops in that region. They are 
pigmented so as to appear reddish brown, the pigment granules 
being generally grouped most thickly near the nuclei. 
The hind-intestine may be divided macroscopically into a large 
posterior portion beginning in the seventh segment, and a small 
intestine only about the length of one segment, and rather nar¬ 
row. In the circular furrow formed by this narrowing of the 
alimentary tract the distal folds of the Malpighian tubules are 
very numerous. The anus is a vertical slit in the posterior end 
of the ninth segment, between the projecting parts on which are 
borne the prolegs. 
When examined microscopically by means of sections, the 
oesophagus is found to consist of an epithelium of thin flattened 
cells, lining which is a chitinous layer bearing groups of chit- 
inous spines, which point backward toward the mid-intestine. 
From two to eight or nine spines constitute a group. (Fig. 2.) 
The muscular coats consist of an inner circular and an outer 
longitudinal layer, both being striated. Sections, both longi¬ 
tudinal and transverse, show clearly that the fore-intestine is 
telescoped into the mid-intestine for a short distance. The 
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