878 CHARLES PauL ALEXANDER 
as discussed elsewhere in this paper (page 705). Riedel (1909: 29) 
describes in some detail the habits and swarming of H. bicolor (Meig.), 
the males of which are very active in the forenoon during the hours of 
brightest sunlight, the females resting on the willow branches near by. 
Similar habits are recorded by Riedel (1910:30) for H. saxonum (Lw.). 
The immature stages of the European species are practically unknown, 
the only original reference being that of Von Réser (1834), who states that 
the larvae of H. nigra Latr. live in the sand along the banks of streams. 
Hexatoma megacera (O. 8.) 
1859 Anisomera m2gacera O.S. Proc. Acad. Nat. Sci. Phila., p. 242. 
The adult flies of Hexatoma megacera are on the wing during the month 
of May and June and may be swept from the rank vegetation along th 
streams from which their larvae emerged. The following notes on copu 
lation, resting positions, egg laying in nature and in captivity, and othe 
details, are quoted from published field observations (Alexander, 19f5 ¢: 
143-145) : 
May 14, 1911— This usually rare insect was common on a grassy plot of land alon 
Cascadilla Creek [Ithaca, New York]. The flies sit on the blades of grass, the long antenna 
of the male directed straight ahead. The males are very poor fliers and prefer to drop to th 
ground when disturbed and clumsily work their way off along the ground. When approach 
from the side they are much more easily alarmed and fly away. When approached fro 
above, they do not move until the stick, finger, or whatnot, is within a couple of inches 
when they remove the fore feet from the support and, on nearer approach, fall to the groun 
When in copulation, the female tries to disengage by rapidly vibrating the wings in attempte 
flight, repeating this often, from every one to five seconds until disengaged or exhauste 
The male can disconnect himself at will. In copulation the female is always uppermos 
unless exhausted, when both sexes lie flat on a grass-blade. The female has the head u 
the male the head downward; copulation always takes place on a vertical support, usuall 
a blade of grass, sometimes a plant stem. The sexes remain in copulation for quite a lon 
time and are perfectly motionless. All of the legs of both sexes are on the support unle 
in a position where this is physically impossible, in which case as many as possible are use 
the hind legs of both sexes are held at right angles to the support, the forelegs in front. Aft 
copulation the female generally drops to the ground, the male, after a few moments’ rest, fli 
away. Specimens in copulation were found in abundance from 2 to 4.30 p.m. when no mor 
could be discovered. From 4.30 to 7 p.m. solitary males were common, but no females coul 
be found on the grass-blades. At 4.30 p.m., a few females were found clinging to the tr 
of the willow trees about two feet from the ground. At 5.30 p.m., females were noted i 
small groups over the water, evidently engaged in oviposition, as they frequently dippe 
down to the surface. These latter were in company with a large swarm of dancing empidi 
flies (Rhumphomyia). Of the great numbers that were picked from grasses in the afte 
noon a considerable proportion were females and toward 5 p.m. they commenced egg-layi 
on the sides of the containing vessel, large shell vials. By 7 p.m. the sides of the vials we 
black in places with the large, dark-colored eggs. This data would seem ta place the ti 
for oviposition at about sunset. The females are very good fliers and often travel for lo 
