40 Wisconsin Academy of Sciences, Arts and Letters . 
ing through the head, runs in a posterior and slightly dorsal 
direction, until a position ventral to the brain is reached; here 
it passes over into the oesophagus, which, instead of continu¬ 
ing in the same direction as the pharynx, makes an angle with 
it and continues parallel to the long axis of the body. 
At its beginning, the oesophagus is as wide as the pharynx, 
but it gradually narrows and passes as a thin tube straight 
through the head and thorax. At the anterior end of the abdo¬ 
men, the oesophagus dilates to form the crop, which, when dis¬ 
tended, extends back as far as the sixth abdominal segment 
(Fig. 2, c ). When, however, the crop is not distended, its 
wall is folded irregularly and, from an external view, is hardly 
distinguishable from the oesophagus. 
The gizzard is in the form of a short cylindrical tube; ante¬ 
riorly it is pushed into the crop, while posteriorly it is tele¬ 
scoped far into the mid-intestine. From an external view, the 
only portion visible is a small, slightly curved intermediate 
piece (Fig. 2, g). 
The mid-intestine is a straight tube which is widest at the 
middle third of its length. This region of the alimentary canal 
presents a series of circular folds, which are perpendicular to 
its long axis (Fig. 2, md). A microscopical examination of 
the outer wall shows that there are a number of parallel longi¬ 
tudinal muscles, which send branches into the folds. At the 
anterior end of the mid-intestine these muscles leave it and 
attach to the gizzard; at its posterior end they pass backward 
between the Malpighian tubules, and some continue as the 
external longitudinal muscles of the ileum. 
The Malpighian tubules, ninety to one hundred in number, 
enter the mid-intestine near its posterior end. A little dis¬ 
tance back of their entrance is a constriction, which marks the 
boundary of the mid-intestine and hind-intestine. Bordas (3) 
claims that, “Chez les Tenthredinidae (Emphytus ), les tubes 
de Malpighi, en nombre tres restreint, de 20 a 25, sont inserts 
sur une seule rangee circulaire, un peu arriere de la portion 
retrecie du tube digestif, situee entre l’intestine terminal.” 
According to Bordas, therefore, the Malpighian tubules of 
Emphytus, a Tenthredinida, must enter the hind-intestine, be- 
