Bigs oh i W! 
VOL. XXV DECEMBER, 1918 No. 6 
ON THE STRUCTURE AND FUNCTION OF THE PRO- 
VENTRICULUS OF. GRYLLUS PENNSYLVANICUS 
BURM. 
By E. Metvitte DuPorte, 
Macdonald College (McGill University), Canada. 
There are two explanations generally given of the function of 
the proventriculus in insects. The earlier writers regarded this 
organ as the analogue of the gizzard of birds, an organ for the mas- 
tication and comminution of the food in its passage from the crop 
to the mesenteron, hence the terms “gizzard,” “gesier,” ‘‘ Kaum- 
agen.” 
Another view, and one which perhaps has now the greater 
number of adherents, is that the teeth of the proventriculus have 
no triturating function but act as a strainer or grating to exclude 
solid particles of food from the mesenteron. While some writers 
deny completely the comminuting function of the proventriculus, 
others are willing to admit that in addition to its straining action 
it may sometimes have a triturating action. Still others hold that 
one of the chief functions of this organ is to thoroughly mix the 
food from the crop and prepare it for the action of the digestive 
juices in the mesenteron. 
The writer hopes to show from a study of the structure of the 
proventriculus of G. pennsylvanicus and of the condition of the 
food in the crop, the proventriculus and the mesenteron, that in 
the Gryllidz the proventriculus has a definite triturating function. 
The descriptions are limited to G. pennsylvanicus because for his 
purpose the armature of the proventriculus in all of the Gryllide 
studied by him is essentially similar. 
As the proventriculus of other species of the Gryllidz has already 
been described the structure will not be given in very great detail. 
The anterior division forms a tubular neck leading from the 
crop. The intima is thrown up into six folds each bearing ten 
