PSYCHE 



VOL. XXV DECEMBER. 1918 No. 6 



ON THE STRUCTURE AND FUNCTION OF THE PRO- 

 VENTRICULUS OF GRYLLUS PENNSYLVANICUS 



BURM. 



By E. Melville DuPorte, 

 Macdonald College (McGill University), Canada. 



There are two explanations generally given of the function of 

 the pro ventri cuius 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 Gryllidse 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 Gryllidse 

 studied by him is essentially similar. 



As the proventriculus of other species of the Gryllidse 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 



