526 CG. GORDON HEWITT. 
figure (fig. 25), it is rather similar to the proventriculus of the 
imago in general structure. The cesophageal epithelium 
penetrates a central core which is composed of large clear 
cells (c. c.) ; its lumen, being cesophageal, is lined with chitin. — 
This core is surrounded by an outer sheath, the cells (e. v.) of 
which are continuous with those of the ventriculus. At the 
junction of the central core with the outer sheath of cells 
there is a ring of small more deeply-staining cells (7.c.). 
This ring was regarded by Kowalevski (1887) as the rudi- 
ment of the stomodzeum of the nymph, but Lowne is of the 
opinion that it develops in the nymph into the proventriculus 
of the imago. I believe that it forms a portion, at least, of 
the proventriculus of the imago, as it exhibits a very close 
resemblance to the ring of cells in this region figured in the 
section of the proventriculus of the imago (fig. 20 of Part I). 
The mesenteron of the mature larva is of very great 
length, and is not divisible into the two regions of 
ventriculus and small proximal intestine as in the imago, but 
appears to have the same character throughout; hence Lowne 
calls it the “ chyle-stomach,” which term, or ventriculus (fig. 
29, v.), may be used to designate the whole region from the pro- 
ventriculus to the point at which the malpighian tubes arise. 
It is very much convoluted and twisted upon itself. The 
course of the ventriculus is almost constant, and can be better 
understood from the figure than from any detailed description. 
At the anterior end four tubular ceeca (c. v.) arise. Their 
walls consist of large cells whose inner faces project into the 
lumen of the glands; these glands were not present in the 
imago. ‘he epithelium of the ventriculus (fig. 30) 1s com- 
posed of large cells (e. v.), which project into the lumen of 
the alimentary tract ; they possess large nuclei and the sides 
of the cells facing the lumen have a distinct striated appear- 
ance, which is absent in those epithelial cells covered with a 
chitinous intima. ‘This striated appearance may be related 
in some way to the production of the mucous intima which 
is generally present in the ventriculus, and which appears to 
take the place of the loose chitinous intima or peritrophic 
