BEHAVIOR OF SPIDERS AND OTHER INSECTS 387 



titania resembles that of the English sparrow. With his wings 

 half spread, displaying the beautifully colored hind wings, the 

 male performs many antics. 



Sturtevant (116) has performed some experiments upon sex 

 recognition and sexual selection in Drosophilia ampeliphila. By 

 putting a female in one vial and a male in another and placing 

 the vials mouth to mouth, with a cover glass between them, it 

 was found that the male pays no attention to the female until 

 the cover glass is removed. This observation, coupled with the 

 fact that they mate in darkness, forces the conclusion that vision 

 is not essential for their mating. Experiments demonstrated 

 that the female will mate with either normal or mutilated males; 

 but males with entire wings mate sooner than those with muti- 

 lated wings. Hence he concludes that the wings play a promi- 

 nent part in arousing sexual excitement, but that there is no 

 evidence of sexual selection. A specimen that is ready to mate 

 will do so with the first member of the opposite sex that happens 



along. 



MATERNAL INSTINCTS 



Back and Pemberton (5, 6, 7) have discussed the ovipositing 

 of the Mediterranean fruit-fly and the melon-fly; Blackman (14), 

 of Pityogenes hopkinsi; Dunn (32), of Dermacentor nitens; Essen- 

 berg (34), of the water-strider ; Fuller (43), of some South African 

 termites; Hancock (55), of katydids; Kennedy (68), of dragon- 

 flies; Schwarz (106), of Catocala titania; and C. L. Turner (120), 

 of the camel cricket. 



Severin (107) thinks that the perception of the digestive fluids 

 through the micropyle of the egg causes the larva of the leaf- 

 ovipositing Tachinidae to begin to free itself from the egg. 



Hegner (58) so manipulated the eggs of the potato beetle that 

 35 batches were in the sunlight and 15 in the shade. All of the 

 eggs in the shade hatched; but none of those in the sun, although 

 18 developed to the hatching point. Sections of the eggs showed 

 that development had proceeded in the sunlight and that the 

 failure to hatch was probably due to dessication. He concludes: 

 " The advantage of concealment is not so great therefore as that 

 secured by shielding the eggs from the dessicating properties 

 of the sun." 



By adding spiders to and abstracting spiders from the nests 

 of mud-dauber wasps, Rau (101) demonstrated that sometimes 



