6 THE NORTH AMERICAN SPECIES OF DROSOPHILA. 



26 minutes, respectively, but the beginning of these cases was not 

 observed; 11 minutes is, however, probably unusually short for this 

 species. 



Drosophila caribhea: Scissors movement, circling, licking, abdomen 

 bent up underneath; no vibration seen. In copula about 10 minutes. 



Drosophila funebris: Scissors movement, licking, abdomen bent up 

 underneath; no circling or vibration. One wing is sometimes slowly 

 spread to a right angle with the body and then relaxed, without vibra- 

 tion. This motion, which occurs in some other species, I have called 

 *' waving." In this species, unlike any of the preceding, the female 

 spreads her wings apart before mating, and the male normally does 

 not attempt to mate until she does spread them. After she spreads 

 them he may mount, and copulate as he does so; he may continue 

 licking, or he may partially mount and not copulate. Even if mating 

 does not occur, the female holds her wings spread apart for about a 

 minute. I removed the wings from two females and placed males 

 with them. In this case the males seemed not to wait for the females 

 to spread the stumps of wings that remained, but attempted to 

 mate before that happened. In copula 13, 14, 16, 18, 18, 19, 20 

 minutes. 



Drosophila hydei: As in D. funebris. Copulation may be repeated 

 within 30 minutes. In copula 1, 1, 1, 1, 2, 2, 2 minutes. 



Drosophila immigrans: Scissors movement, waving with both wings 

 at once, licking, male genitalia go up underneath ; no circling or vibra- 

 tion; female does not spread her wings. The position of the legs of 

 copulating males of this species has been observed in several cases, 

 and has been found to be quite variable, as it probably is in all species. 

 In copula 15, 53, 54, 55 minutes. The female is very restless for about 

 the first 10 minutes. 



Drosophila lutzii: No scissors movement, vibration, or circling seen. 

 The male stands behind the female, with his head under her wings, 

 and often stays thus quietly for some time. Then he pushes up 

 against her wings jerkily with his head, at the same time bending his 

 abdomen around to one side. During this act his long axis is not 

 quite parallel to that of the female, and the abdomen comes around 

 the shortest way. The female spreads her wings, and the genitalia 

 come together at almost the same time. The male then mounts, his 

 final position being that which is usual for the genus. Two copulations 

 timed, each lasting about 1 minute. 



Drosophila melanica: Not observed in detail, but scissors movement 

 and licking seen. 



Drosophila nebulosa: Vibration, scissors movement, licking, but not 

 much of any of them. The male stands facing the female, in front of 

 her and a little to one side. He waves the wing on the side toward the 

 female several times rapidly, at the same time bending his abdomen 



