206 ENTOMOLOGICAL SOCIETY 
In several groups of insects only the males could be separated, 
the females being indistinguishable. 
Prof. Riley replied that in Microgaster the females were gen- 
erally the better characterized, but in a few* it was the males. 
The male antennae and the female ovipositor often gave the best 
characters. 
Mr. Marlatt read the following : 
SWARMING OF LYC^ENA COMYNTAS, GODT. 
BY C. L. MARLATT. 
About the middle of July, 1888, the writer's attention was drawn to the 
large numbers of small butterflies, of the species above named, flitting with 
irregular but rapid flight back and forth at a height of 25 to 30 feet from 
the ground, above some elm trees which grew alongside a large field of 
red clover. Occasionally one would rest for a second or two on the upper 
part of an elm, only to quickly resume its place in the swarming mass 
above. 
No easy explanation of the peculiar congregating of these butterflies pre- 
sents itself. So far as observed, it was not a nuptial flight no union of 
the sexes occurring. There was no general movement in any direction, 
but their actions seemed rather of a playful or frolicsome nature. They 
had evidently come together from the clover-field mentioned, in which 
they had been breeding abundantly. 
A threatening storm of wind and rain coming on at the time may have 
had something to do with their collecting into swarms. 
An additional instance may be given, which indicates still further a 
semi-gregarious habit with these insects. The writer has observed them 
in later summer covering moist patches of ground in such numbers that a 
single sweep of a net would capture 50 or more of them. Their object in 
this instance was evidently to suck up the moisture, the extremely dry 
weather having doubtless greatly reduced the supply of nectar in the 
clover-blossoms. 
Mr. Smith said that it could hardly be a nuptial flight, for this 
species copulates over its feeding-grounds in the fields. 
Mr. Schwarz said that Benton had lately recorded an instance of 
a " flock" of butterflies in New Guinea, which covered a couple 
of acres of ground where there were no flowers for food. 
Prof. Riley thought this note very interesting, and said that 
whenever, from whatever cause, a species of insect becomes ex- 
tremely abundant it almost invariably swarms and has some pe- 
culiar flight. He mentioned an instance, which came under his 
