384 HARRY H. CHARLTON 



OBSERVATIONS 



External sexual characters 



During the spring months of March, April, and May, the adult 

 insects are in the best condition for study, but since it takes 

 some time, probably a year or more, to attain sexual maturity, 

 the early stages may be studied at any time of year in young 

 individuals. 



It is comparatively easy to recognize the sexes by their external 

 appearance. The female (fig. 2) has a long median ovipositor 

 extending posteriorly which is quite prominent in the living 

 insect. There is nothing comparable to it in the male (fig. 1), 

 for the penis which could not possibly be confused with the 

 ovipositor is more often retracted and not in view. 



Male reproductive system 



The testes (fig. 3), of which there are three pairs on each side 

 of the middorsal line, occupy, in mature individuals, a consider- 

 able portion of the anterior two-thirds of the abdomen. The 

 testes lie parallel to each other, extending in a ventroposterior 

 direction, and each is connected by a short duct with the vas 

 deferens, which passes as a straight duct posteriorly where it 

 enlarges to form the seminal vesicle. From the seminal vesicle 

 a similar duct extends, which soon enlarges considerably and, 

 after bending upon itself a couple of times, opens into the base 

 of the penis. 



Spermatogonia 



I have made a long and careful search for primary spermato- 

 gonia in the youngest material at my disposal, which consisted 

 of insects only 2 or 3 mm. long, but have not been able definitely 

 to identify them. It is therefore very probable that the primary 

 spermatogonia occur only very early in the life-history. Mun- 

 son ('06) has described an apical cell which produces early 

 spermatogonia, but this, too, if present at all, would be found in 

 exceedingly young individuals. 



