118 Annals Entomological Society of America [Vol. IX, 



One of the most important of these special phases is that 

 which attends the breeding activities and it is mainly with this 

 aspect that this paper is concerned. It is impossible to describe 

 the reproductive habits of all the Orthopteran forms as literature 

 does not exist which would give the desired information. The 

 activities of enough forms have been described, however, to 

 permit a general comparison and a few generalities from the 

 evidence thus presented. 



The series of movements into which the entire process of 

 reproduction may be divided will be considered separately and 

 will be compared as units through the different famiHes. 



MOVEMENTS PRELIMINARY TO COPULATION. SEX DISCRIMINATION. 



In some of the Orthoptera the movements preliminary to 

 copulation are exceedingly simple. In others there is a com- 

 pHcated series of activities. Behaviour is the only criterion by 

 which we may judge sex discrimination. It has been suggested 

 that any movement which would indicate excitement after the 

 two animals have come within sensing distance of each -other 

 might indicate recognition of sex. It must be borne in mind, 

 however, that some of the Orthoptera are in a state of continual 

 excitement during the breeding season, especially is this the case 

 with males which have once copulated. In this state of 

 excitement males will seize other males, members of other 

 species or even a stick to which the abdomen of a female has 

 been attached, so that it is not safe to base sex discrimination 

 upon this one peculiarity of behaviour. On the other hand 

 there is an entire lack of movements that would indicate excite- 

 ment in some forms. Here the problem of sex discrimination is 

 just as puzzHng. No general statement in regard to sex dis- 

 crimination would hold and each case must be considered 

 separately. 



The records of the sexual activities of the Blattidse are very 

 meager and in no case have their habits been described in detail. 

 The sense of hearing is obviously not a factor as there are no 

 organs for the reception of sound. Sight plays some part, for 

 the male is described as running about the female traihng his 

 abdomen and attempting to induce her to become quiet, even 

 before they have come into contact with their antenna. The 

 senses of touch and of odor must play some part although no 

 statement can be made as to their relative importance. 



