HUNGERFORD: AQUATIC HEMIPTERA. 103 
ing a wide groove, reminding one, when in action, of the tip of an apple 
corer. Upon dissection it is seen to be made up of three parts, two 
lateral shafts that are strongly chitinized and toothed or serrated along 
the lower portion of their lateral margins and a broader central plate. 
The lateral shafts are attached to the flat plates of the abdominal wall. 
The central portion is in reality made up of paired parts attached to 
the median pair of sclerites that serve as the valves or shields for the 
ovipositor. 
The manipulation of this instrument during oviposition may be ob- 
served any time during the spring, summer or autumn by confining a 
number of mating insects in a petrie dish containing only clear water 
and some food. After being thus deprived for a couple of days of 
materials in which to place their eggs, they will gather about a small 
bit of sedge stem or cattail leaf supplied them, and most eagerly set 
about the business of laying eggs. The writer has seen as many as 
eight thus employed about a portion of sedge stem one and one-half 
inches long, and has had ample opportunity to watch the process under 
the binocular. 
The female frequently explores the stem with the tips of her beak 
and antenne if indifferent in the matter, but if eager to oviposit, she 
_ mounts the stem without delay, raises the abdomen slightly, unsheaths 
the ovipositor and turns its tip down to the surface of the stem. At 
times the surface is tested out at several points—again if the first point 
of contact is favorable, the tip is caused to quiver back and forth till 
it gains a footing, and then rocking the body slightly from side to side 
the entire drill is caused to rotate or twist back and forth on its axis, 
rapidly at times, or again more slowly as may suit the necessity of the 
work, until a hole is effected and the ovipositor is buried to its base. 
During the deeper drillings the longitudinal alternate thrusts of the 
drill parts are apparent. The first part of the operation at least in- 
volves much the same sort of motion as one employs in making a hole 
with a gimlet or awl. It takes but a moment in the spongy, water- 
soaked stem of a sedge to drive the instrument up to its base. Then, 
after a moment of apparent quiet, the ovipositor is lifted slightly and 
the egg is forced by a series of abdominal contractions down the ovi- 
positor and into the cavity reamed out to receive it. 
The egg when forced into the ovipositor distends it considerably as it 
passes through its channel and thus can be seen to slip down into posi- 
tion with its distal end directed forward beneath the insect. The ovi- 
positor being at last withdrawn from beneath, the egg slips out from 
behind the exposed circular end of it. 
A number of eggs may be imbedded thus, in the stem, before the 
ovipositor is sheathed, each one requiring a separate puncture. In the 
cylindrical stems of plants procumbent upon the water the eggs are 
_ likely to be inserted on the sides as they come in contact with the sur- 
- face film, but this is by no means necessarily the case. 
As frequently as not the male accompanies the female during the 
process. Having mounted her in mating, he merely moves forward and 
