1922] Walker: Structure of Orthopteroid Insects 49 



but it is closely connected with the latter and in other species 

 seems to form a part of it. 



This dorsal plate bears some resemblance to that of the 

 right side and is probably its homologue, though not a free 

 flap as in the latter case. 



The inner surface of the lobe is for the most part mem- 

 branous, but there are two small, though heavily chitinized, 

 plates, which lie close to the mouth of the ejaculatory duct. In 

 S. floridensis one of these is prolonged into a flagellum, while in 

 Mantis religiosa they are both short and spinulose. These 

 parts appear to represent the small sclerite which occupy a 

 similar position in Periplaneta. There is no evident represen- 

 tative of the ventro-mesial process, unless it be one of these. 

 The ejaculatory duct is a large tube passing between the two 

 lobes, which are virtually wrapped around it. It opens upon 

 the inner, membranous surface of the sinistral lobe, imme- 

 diately beneath the two small, dark, inner sclerites. There is 

 only the feeblest indication of an asdeagus. 



Isoptera. 



The same two species of "termites" were studied as in the 

 case of the females, viz., Termopsis angiisticollis Hagen and 

 Leucotermes flavipes Kollar. The results of this study supple- 

 ment those obtained from the females in showing that the 

 Isoptera are most nearly related to the Blattoidea and Man- 

 toidea, and form with these groups a distinctly natural 

 assemblage. 



The general appearance of the end of the male abdomen in 

 Termopsis angiisticollis (Figs. 76; 77), is similar to that of the 

 female, but, as in the Blattids and Mantids, differs in the 

 presence of styli. The character of the segmentation agrees 

 closely with these groups. The last three tergites are, like those 

 of the female, curved slightly ventro-caudad, all being much 

 shortened laterally. The tenth is considerably enlarged and 

 takes the place of the supra-anal plate, which is not present as 

 a distinct structure. Close to the ventro-caudal margins of the 

 tergites are the spiracles. The cerci are similar to those of the 

 female. 



The sternal region is quite blattoid in structure. The 

 sternum of the ninth segment forms a large, undivided, sub- 

 genital plate, bearing a symmetrical pair of styli on the caudal 



