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Psyche 
[Vol. 95 
rocking movements observed in pairs (a screen prevented these 
females from walking down into the vegetation; genital contact 
terminated after about two minutes but the male remained on the 
female and continued to execute courting movements). The dorsal 
and forward force generated during male lifting movements 
probably came from his hind legs, which were usually braced on the 
substrate. Probably the effect of the rocking movements was to drag 
the female slightly forward by her genitalia. 
In each of the ten courtship sequences in which I observed termi- 
nation, the female walked down into the vegetation. In all but one 
case, when the male was scraped off by protruding vegetation, the 
male was still riding on her dorsum when she disappeared. The 
dislodged male hovered for several seconds about 5 cm over the site 
where the female had disappeared, then flew away. Females prob- 
ably oviposited when they walked down into the pile of vegetation, 
as flies were raised (14 males and 15 females) from a pile into which 
mated females had disappeared. 
Discussion 
There are several reasons for classifying the behavior of copulat- 
ing males as courtship. The patterns were relatively stereotyped, 
both in form and, to a lesser extent, in sequence; the males’ move- 
ments undoubtedly caused stimulation of the female; they were per- 
formed consistently in male-female interactions and never in other 
contexts; and they were unlikely to have any other functions for the 
males. None of the movements described was performed before 
genitalic coupling was achieved, while all males made at least some 
of the movements soon after coupling began. It is unlikely that the 
post-coupling male behaviors were some sort of selectively irrele- 
vant “overflow” courtship, because they never began until after 
coupling had occurred. 
Demonstration that male H. nigrifemorata only court females 
after achieving genitalic coupling supports the idea that post- 
coupling courtship in this and, by extension, other species with 
post-coupling courtship can be selectively significant. This demon- 
stration of the importance of cryptic female choice is, in turn, in 
accord with the argument that male genitalia are often selected to 
perform “internal courtship” after intromission has begun (Eber- 
hard 1985). 
