3 32 



MR. U. F. CUMMINQS OX THE 



Text-fig. 25. 



^ /^ 



DiAGKAM to illustrate the evolution of the hjpopliarynx. 

 (I) lApeurus. (2) Lcemohothrium . (3) Hypothetical. (4) Aneistrona. 

 A, edge of labium ; B, anterior compound plate ; C, cesophageal sclerite : D, " duct ' 

 E, rami; F, "glands" or lateral pieces; G, anterior cornu. 



