MALE GENITALIA 



45 



homologous with the inner valves. Also, Walker's figures (1919) 



of the developing ovipositor of the grasshopper Conocephalus are 



suggestive of a similar homology. On the other hand, careful 



ontogenetic studies are needed from the first instar onwards in 



order to ascertain whether or not any change in the relative 



positions of the valves in question takes place during growth. 



The study by Denny (1897) of the ovipositor of Blatta orientalis 



shows that the anterior and posterior valves are homologous 



parts, the lateral valves alone 



being derived from coxites. It 



would seem remarkable if, in 



such closely allied genera as 



Blatta and Blatella, the anterior 



valves of the ovipositor should 



develop in a different manner in 



the two cases, and it is evident 



that further research is necessary 



before any conclusions to the 



effect that the lateral ovipositor 



valves are of different origin 



among insects belonging even to 



the same major group. 



The Male. In the males of 

 those insects whose genitalia are 

 fully developed two sets of 

 organs, forming the completed 

 parts, are present. These organs 

 arise from rudiments which 

 develop in relation with the ninth sternum of the abdomen. The 

 outer organs are known as claspers, harpagones or valves and are 

 the functional organs used for grasping the abdomen of the female 

 during coitus. These organs will be considered first. They are 

 commonly regarded as developments of the coxites of their 

 segments, but Snodgrass (1935, 1936) has claimed that the balance 

 of evidence is in favour of their being regarded as modified styli 

 rather than coxites (Fig. 28). As this morphologist points out, 

 the claspers are movable lobes which, in some cases, are supported 



Fig. 27. Ventral terminal abdominal 

 segments of a female soldier of 

 Mastotermes. c, coxite ; c', base of 

 cercus ; g, ventral or anterior valve 

 of ovipositor ; g\ intermediate or 

 posterior valve of ovipositor ; pa, 

 paraproct ; S^-S^, seventh to 

 ninth sterna ; s', stylus or dorsal 

 (lateral) valve or ovipositor ; tj^^, 

 tenth tergum. (Adapted from 

 Crampton.) 



