HANCOCK 15 



the sexual habits of insects, and these little orthoptera are 

 not without interest in this regard. 



In the spring the male and female effect conjugation, vary- 

 ing from a few hours to days before the egg-laying process 

 commences. In Tcttigidea the two sexes often stay together 

 for some days at a time. The male, being much smaller, rides 

 about on the female's back unless she rids herself of his pres- 

 ence by a vigorous jump. During actual conjugation the 

 subgenital plate of the male is capable of being lifted up from 

 a horizontal plane to nearly upright. Its superior surface is 

 grooved in the middle and it is anteriorly obtusely angulate. 

 This superior portion answers as a shield which covers the 

 opening of the spermatic ducts. It is upon this obtusely 

 pointed anterior border that the edge of the last abdominal 

 segment (sternum) below the female ovipositor is clasped, thus 

 affording a hold and retaining the proper position of the geni- 

 talia during copulation.* The superior shield or surface 

 ordinarily when at rest is covered partly by the pointed supra- 

 anal plate. The difference in their positions in activity and 

 repose is extraordinary, the stuctures in activity being drawn 

 out of any semblance to their passive position; and it must 

 be remembered the anterior border of the shield is not at all 

 observable ordinarily, only that part behind showing which is 

 not covered by the supra-anal plate. 



In Tcttix the two sexes do not often remain long in copu- 

 lation, often only a few minutes at a time. During the active 

 egg-laying period the female is sought after by the males. 



POLYANDRY AMONG THE TETTIGID^. 



The existence of polyandry among the Tettigidae forms an 

 important factor in accounting for variations. In those species 

 where the sexes remain longer together, as in the genus Tctti- 

 gidea, the extent of polyandry is not so great as among Tcttix 

 and allied genera, in which the individuals stay together but 

 a short period, thus allowing a greater number of males access 

 to the female. It will be remembered that among Tettix and 



* In some orthoptera chitinous hooks arm the caudal end of the penis. 



