144 
Psyche 
[December 
amounts of food, and either extended or retracted with 
large quantities, was not supported in the present study. 
In the four corixids with the shortest invaginations, the 
midgut was empty. Sutton’s claim that the intravalvular 
space contains a blood sinus mlay be true, but there is no 
evidence from the present study to support her theory that 
the valve takes an active part in moving the food posterior- 
ly into the midgut. 
Fig. 3. Diagram of the esophageal invagination of Sigara ornata or 
H esperocorixa interrupta. Legend same as for Text - figure 1. Dotted lines 
indicate region from which Figure B (Plate 12) was taken. 330X. 
