8 THE NORTH AMERICAN SPECIES OF DROSOPHILA. 
The male rushes at the female, with his abdomen bent up underneath, 
and grasps her wings with his front legs, holding them between his 
femora and tibiz. The comb of bristles on the front femora, a second- 
ary sexual character occurring in all the species of the genus known 
to me, seems to be connected with this holding of the wings. The 
female struggles when caught, and usually escapes. If she does not 
escape immediately she soon becomes quiet, and the male attempts to 
mate. No successful copulation has been observed, though in one 
case a male kept hold of the wings of a female for 15 minutes and 
repeatedly attempted to mate. 
Chymomyza procnemis: The male runs after the female, and when 
she stops pushes her wings apart with his head, grasps them with his 
front legs (as in C. amena), mounts, and attempts to mate. He 
repeatedly grasps the region of her ovipositor with his large genital 
claspers, the abdomen being bent up underneath. Usually after 
about a minute copulation occurs. In copula 8, 9, 18, 18 minutes. 
The forms described may be roughly classified as follows: 
—_ 
. Mounting before copulation; male holds wings of female: Chymomyza amena, C. 
procnemis. 
. No wing courtship; abdomen goes up at side: Drosophila lutzit. 
. All wing movement in front of female; abdomen bent around at side; female spreads 
her wings: Drosophila nebulosa. 
. Little wing-movement; female spreads her wings: Drosophila funebris, D. hydei, D. 
repleta, D. virilis. 
5. No vibration; female does not spread her wings: Scaptomyza adusta, S. graminum, 
Drosophila caribbea, D. cardini, D. immigrans, D. robusta, D. willistont. 
6. Vibration, circling; female does not spread her wings: Drosophila affinis, D. busckii, 
D. melanogaster, D. obscura, D. simulans. 
Insufficient data: D. hypocausta, D. melanica, D. transversa. 
aad Ww bo 
The members of the genus Chymomyza mount before copulation; 
in Drosophila and Scaptomyza copulation precedes mounting. The 
former relation is the one that appears to be usual among other Mus- 
cide. It occurs in the Calyptere in general, and in all the Acalypterze 
that I have observed, belonging to the subfamilies Sepsinz, Piophiline, 
Trypetine, Borborine, and Ephydrine. 
The final position of mated pairs is in general the same throughout 
the group of Drosophiline, so far as observed. The same position is 
the rule in the rest of the Muscide. I have observed it in many 
Calypterz and in the acalyptrate subfamilies mentioned in the pre- 
ceding paragraph, as well as in the Cordylurine. It occurs in some, 
but not in all, Syrphide. The only exception known to me among the 
Muscide is in the case of the genus Lonchewa, one mated pair of which 
I have observed. This pair was in the end-to-end position; but 
that may not be the normal process for the species (apparently L. 
polita Say). 
