HUNGERFORD: AQUATIC HEMIPTERA. 135 
the “Veliine of the Atlantic States,” and also contributed to the biology of 
two species of Microvelid. The writer has reared but one species in this 
family, M. borealis. 
Genus MICROVELIA Westw. 
The two species that have been reared in this country are M. americana 
and M. borealis. The former about the largest and the latter the smallest 
of the genus. Bueno has published the life history of the latter just 
recently (Oct., 1917) in Ent. News. The writer reared this species in 
the summer of 1916. 
Microvelia americana Uhl. 
Habitat. Bueno says: “Many an entomologist when drinking from a 
field or roadside spring has noticed the tiny black, silver-spangled insects 
that detach themselves from the stones forming the basin, and run across 
the surface, or glide out from the side and swiftly curve in to their former 
resting places. This is M. americana Uhl. It is to be found on the banks 
of any body of water, moving or still. Where the walls of the spring or 
the bank of the stream or pond are more or less vertical, they perch a 
little above the water. But on shelving or sloping banks they wander 
about over the mud or pebbles, seeking their prey, leaving the shore only 
when alarmed or disturbed. They also concea] themselves under the 
overhanging banks of streamlets, as observed by Uhler in Maryland, and 
the writer in New Jersey. 
Hibernation. They hibernate in colonies beneath the overhanging 
banks of little streams in the middle states. (Uhler.) 
Mating. Mating has been described in some detail by Bueno. (See 
f Can. Ent.,:p. 180, 1910.) 
Oviposition. The eggs are white oval bodies, and are placed singly or 
in clusters fastened to the support by an abundance of transparent gela- 
tinous material, as a rule, just above the surface of the water on pebbles, 
jutting stones and the like. 
Incubation. Bueno says the egg stage lasts two or three weeks or 
less. The eggs grow darker, and at one end the red eyes, the legs, the 
rostrum, etc., of the nymph are visible through the shell. 
Number of Instars. Bueno describes five instars, each one requiring 
from 2 to 10 days, the last stage being the longest. 
Molting. “In molting the skin of the head splits along the eyes, and 
rises like a lid at the front. In the body, it splits longitudinally along 
the middle line of the thorax, and down the dorsum to the third or fourth 
abdominal segment. The rostral lancets are molted entire, including 
their insertion in the interior of the head, as well as the trachezx.”’— 
Bueno. 
The above applies to any other strider. See plate XV for figure of 
molt of Gerris. 
Maturity. These bugs become mature in about 5 days. 
Food Habits. The writer has seen them feeding upon insects dropped 
into the water and catching Ostracods at the surface film. Bueno noted 
them feeding upon water-fleas imprisoned in the surface film. Bueno 
says they are always in a condition of semistarvation, and, when a living 
_ fly is fed them, of course they attack it in full force. When it struggles 
