Mating Ini>thict in Moths. 187 



It is inteiesting" to notice that the females increase in 

 attractiveness as tliey grow older. This was repeatedly 

 demonstrated as follows : — 



Several females, all of which were about six hours old, 

 were confined in a large cage made of mosquito-netting, thus 

 allowing a free circulation of air. The same number of 

 females about thirty hours old Avere placed in another similar 

 cage about six feet away from the younger females. Out of 

 thirty-seven males thirty-five came exclusively to the cage 

 containing the older females. Of the two remaining males 

 one came to the younger females and one divided his atten- 

 tion between both cages. When the females are made to 

 exchange cages the males will still go to the cage containing 

 the older females. 



Upon testing females thirty hours old against females fifty- 

 five hours old, it appeared that they were equally attractive. 

 Of seven males three came to the females thirty hours old, 

 one divided his attention between both cages, and three came 

 to the fifty-five hour females. It thus appears that females 

 about six hours old are not so attractive as are females one or 

 two days old. 



Virgin females are somewhat more attractive than fertilized 

 ones of the same age. When the virgins are placed in a 

 cage five feet away from a cage containing an equal number 

 of fertilized females the majority of the males fly to the 

 virgins. Thus out of eleven males eight came to the virgin 

 females, two to the fertilized ones, and one to both cages. 



Fertilized females are still quite attractive to males, how- 

 ever, and the males will readily mate with them. This last 

 was first observed by Miss C-aroline G. Soule in 1894. She 

 had two female promethia moths, each one of which was mated 

 with four males and still remained attractive to other males. 

 In fact, as long as the female remained alive and in good 

 health she held attractions for the male. 



One of my males mated four times with three females, and 

 three others mated three times each. The males will make 

 frantic eflforts to mate with a female which is at the time 

 coupling with another male. 



The male will fly toward the female with normal eager- 

 ness even though liis entire abdomen be cut off, and he will 

 still seek the female when, in addition to this, the sides of his 

 thorax are covered with impervious glue. It is therefore 

 evident that the spiracles are not the seat of the organs by 

 which the male perceives the female scent. 



If, on the other hand, the antennaj of the male be covered 

 with shellac, glue, paraffin, Canada balsam, celloidin, or 



