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HUNGERFORD: AQUATIC HEMIPTERA. 93 
alge and slime floating on the surface, the color of which it matches 
in the young stages.” We have found it on the Sphagnum at the edge 
of bog ponds in New York, and amidst the Typha, smartweed, spike- 
rush, etc., growing in the shallow pools and ponds of Kansas, as well 
as upon floating rafts of dead typha, or tangles of Spirogyra. It pre- 
fers the footing such supports may offer to the open water. However, 
it can walk upon the water when occasion demands. 
Hibernation. It winters as an adult in the trash about the pool, 
coming out in early spring to resume activity. Wesenberg-Lund, 1913, 
says that the species of Denmark winters in damp moss. 
Mating. There is some difference in the size of the sexes of this bug, 
the male being smaller than the female. Martin says that the peculiar 
habitat of this bug, combined with its elongate form, has given rise to a 
secondary sexual character, which occurs in the H. stagnorum, as well 
as in our own spetvies. This consists of two notched projections on the 
under side of sixth abdominal segment, close to the incisure between the 
sixth and seventh segments. (See pl. XIII, figs. 8 and 9.) The first of 
these notched elevations of the abdominal walls, he says, is to fit over the 
lateral keels of the female abdomen, thus steadying the abdomen of the 
male during copulation.* . This is rendered necessary not only by the 
elongate abdomen, but also by the fact that it is necessary for the insects 
to maintain their balance upon the water or run the risk of breaking 
through the treacherous surface film. 
Oviposition. Martin has given us a splendid account of the oviposition 
of this bug. The writer has often seen the same process. The female 
“exudes from the genital opening a drop of gummy gelatinous substance, 
which she then presses against the object that has been closen to support 
the egg. This sticky mass is the base of the egg stalk, and hardening very 
soon, fastens the egg in place before it has left the body. The insect 
now walks away from the stalk, thus freeing herself from the egg.” 
The newly laid egg is creamy white, which after about half a minute 
quite suddenly changes to a brown, the ends remaining lighter than the 
body of the egg. The material with which the egg is attached appears 
shiny and fluid for several minutes. 
The female places her eggs upon any support, a little Bess the surface 
of the water as a rule. In the aquaria the eggs were placed upon the 
vertical sides of the glass jars from the water level to two inches above 
it. In nature the writer studied a colony of these insects that were living 
on the shallow waters of a pool overgrown by cattail. It was early April. 
The cattail seeds were sending out long sprouts, forming a green mat 
upon the water. The marsh-treaders were laying their eggs upon’ these 
sprouts. The brown spindle-shaped eggs are much the color and shape 
of the cattail seeds, which gives them a striking superficial resemblance, 
which is shown in the photograph on plate VI. 
Incubation. Martin gives 17 days for the duration of the egg stage. 
Bueno says from 19 to 9 or 10 days. In Kansas, eggs laid the afternoon 
of July 16, hatched July 20 in the afternoon, a period of four days! 
* Have observed mating often, but these processes were not used. 
