234 HABITS AND INSTINCTS IN LEPTINOTARSA. 



three or four times, and then becomes quiet again. Copulation lasts from 

 two or three minutes up to ten or twelve hours, the first coitus, however, 

 being usually far longer than those which occur subsequently. When the 

 act is completed the two sexes separate, and within a short time each may be 

 found in copulation with some other individual. 



As far as I have been able to discover, there are no complicated habits asso- 

 ciated with the mating of these beetles, it being effected with the least trouble 

 or ceremony when they are ready for copulation. Rarely, in some species, as 

 in dccemlineata, oblongata, dilecta, and others, the two animals contemplating 

 mating will first feel each other over with their antennae, while others will 

 walk around as if inspecting each other. In oblongata the male will some- 

 times open his elytra to expose the bright red color of his hind wings, but as 

 he is quite as apt to do this when the female is not present it is probable that 

 this action has no particular significance. After these more complicated 

 courting movements copulation is no more apt to follow than it is if the male 

 approaches the female and attempts to begin copulation without any previous 

 ceremony. When compared with the accounts that have been published of 

 the courting habits of various other insects those of Leptinotarsa seem simple 

 indeed. I have often watched for these highly complicated and romantic 

 courtships among insects, but I have not yet been able to see them ; and I 

 should be very much interested to know just how much of the ceremonies 

 described was furnished by the insects and how much by the imagination. 



The directness of the mating of the sexes in Leptinotarsa and its lack of 

 ceremony leaves very little room for the play of sexual selection in these 

 forms, for, although there is no dearth of bright colors, they do not seem to 

 play any part in the bringing together of the sexes. Indeed, the only action 

 that can be interpreted at all as in the nature of ceremony is the opening of 

 the elytra of the male to display the bright color of the hind wings ; but as 

 this is done as frequently in the absence of the other sex as in its presence, 

 and also by both sexes, no one but the extreme advocate of sexual selection 

 could see in this act one of utility as an attraction to the opposite sex. 



The attracting of the two sexes is largely accomplished by the odors 

 secreted by the glands of the body, and especially by the glands of the genital 

 organs. I have often tried the experiment with dccemlineata, oblongata, 

 dilecta, and niidccimlineata of removing the antennae and palps of the males 

 and then turning them loose in an observation cage with a number of females 

 in condition for copulation. As far as observed, the males were unable to dis- 

 tinguish the sex of their companions, and if they attempted copulation at all 

 they were as apt to choose males as females. However, if by accident a male 

 minus his olfactory organs came upon a female and succeeded in mounting 

 her back, he was just as able to copulate as any other male, but he had to 

 depend upon chance to bring him to the female. Under normal conditions a 



