Occasional Papers of the Aliiscitm of Zoology 15 



My idea as to the method of grasping is indicated in the 

 above quotation. Dr. Walker thinks it more probable that the 

 hooks engage the rear of the occiput. I thought it more prob- 

 able that they engage the rear border of the prothorax. We ar- 

 rived at our opinions independently. I think greater weight 

 should be given Dr. Walker's opinion than my own, as he has 

 studied the matter carefully and his experience in the subject is 

 greater than mine. However, it should be noticed that the teeth 

 or projections on the occiput of the female would serve as lat- 

 eral guards for the snout-like apex of 10 in my plan. If, there- 

 fore, as Dr. Walker assumes, their presence in one sex, and not 

 in the other, implies a function, my plan is not weakened by 

 this. As to males of other species in the genus we know noth- 

 ing, but similar modifications of the tenth segment of the male 

 should be expected. Yet the female of in fans has no such 

 occipital projections. It is not impossible, however, that the 

 male of infans, when discovered, will be found to have some 

 structures developed on the dorsum of the tenth segment for 

 engaging -the depressions in the rear of the head of the 

 female. 



It seems to me, however, that the weakest point in Dr. 

 Walker's plan is one to which he calls attention — the immobil- 

 ity of the parts involved. The retention of the female by the 

 male under such circumstances would be almost impossible. 

 Moreover the plan leaves the snout-like apex of 10 without any 

 function. j\Iy idea was that, in seizing the female, the male 

 w^ould place this apex on the dorsum of her head, pushing the 

 rear of the head down, so the occiput would be brought more 

 in Hne with the prothorax, and, this accomplished, the hooks 

 would be snapped behind the hind border of the prothorax. 

 The push upward, by the female's head, on the apex of 10 

 would, I think, securely bind the two sexes together. But 



