Severin and Severin—Anatomical Studies of Cimbex. 49 
come somewhat smaller, and gradually in the Malpighian tu¬ 
bule assume a more or less flattened shape. Each cell con¬ 
tains a single ovoid nucleus, which has its long axis parallel 
to the corresponding axis of the tubule. The striated intima 
is continuous from the wall of the mid-intestine over into the 
Malpighian tubules whose entire inner surface it covers (Figs. 
13 and 14, sm). 
A more minute study of the Malpighian tubules shows that 
in a transverse section the cells are generally six in number and 
arranged in a circle. Each cell is somewhat longer than wide, 
with its inner surface rounded. The striated intima which 
rests upon this rounded surface bounds a more or less sinuous 
lumen (Fig. 9, sm). A peculiarity noticeable in the cells of 
some tubules is the presence of bluish staining globules, which, 
in general appearance, resemble those in the epithelial cells of 
the mid-intestine (Fig. 9, gl). The cells rest upon a base¬ 
ment membrane, external to which is a thin peritoneal mem¬ 
brane (Fig. 9, np). 
HIND-INTESTINE. 
Ileum :—Posterior to the entrance of the Malpighian tubules, 
the mid-intestine continues back a short distance and then pass¬ 
es over into the hind-intestine. Histologically, we find an ab¬ 
rupt change; the long, cylindrical epithelial cells of the mid¬ 
intestine are replaced at the beginning of the hind-intestine by 
smaller cells with relatively small nuclei. The striated intima 
which covers the inner surface of the entire mid-intestine and 
Malpighian tubules is replaced in the ileum by a hyaline chi- 
tinous intima (Fig. 8). 
Pyloric valve :—A longitudinal section through the anterior 
part of the ileum shows the presence of the so-called pyloric 
valve (Fig. 13, pv) [“valvule rectale” of Balbiani, 2 “sphincter 
de Vintestine grele” of Van Gehuchten (15)]. The lumen 
of the canal decreases abruptly in size immediately posterior 
to the boundary between the mid-intestine and hind-intestine. 
Numerous conical, backward-pointing spines project from the 
2 Quoted from Van Gehuchten’s paper. 
4—S. & A. 
