348 Prof. Miall and Mr. R. Shelford on the Structure and 
2. The alimentary canal of the larva. 
The mouth and cesophagus present no unusual fea- 
tures. There is a large cesophageal invagination. A 
capacious cylindrical stomach succeeds, which extends to 
the middle of the eighth segment, where the four 
Malpighian tubules enter the alimentary canal, and the 
intestine begins (fig. 180). 
The transition from the epithelium of the cesophagus 
to that of the stomach is quite sudden.* At this point 
the longitudinal muscles, which were internal in the 
cesophagus, pass through the annular muscles, and 
become external.+ 
The epithelium of the stomach, especially in the 
neighbourhood of the cesophagus, exhibits many narrow- 
necked, rounded protrusions, which push through the 
striated hem into the lumen of the stomach, and at last 
become detached as spherical masses. The protrusions 
are finely granular, andstain well (fig. 22). 
Certain enlarged cells which are particularly numerous 
near the beginning of the stomach, contain peculiar 
granular masses of spherical shape (fig. 23). The 
granular masses are highly refractive, and stain badly or 
not at alls A nucleus is sometimes visible in the same 
cell. The masses occasionally divide within the cell into 
three or four (fig. 23), but the nucleus undergoes no 
corresponding division. The granular masses are 
ultimately discharged entire into the cavity of the 
stomach. || 
We have no conclusive evidence as to the function ot 
either the protrusions or the granular masses. The pro- 
truded spheres have, however, been traced into drawn-out 
layers of fibrous or glairy texture which invest the food, 
and we are inclined to believe that they yield the peri- 
trophic membrane described below. The non-staining 
granular masses are perhaps stages in the formation of 
some digestive secretion.§ 
* Cf. Dicranota (L. C. Miall, Trans. Ent. Soc. Lond. 1893» 
p. 245). ; 
t+ Cf. Balbiani, Etudes sur Cryptops. Arch. de Zool. exp. (2), viii. 
(1890). 
£ See also Dicranota (loc. cit., p. 243). 
§ The mucous or calyciform cells of Balbiani are described as 
staining deeply and uniformly. 
| Cf. Dicranota (loc. cit., pp. 243, 244). 
q Cf. Dicranota (loc. cit., p. 244). 
