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 antennae 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 dowm 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 



