hungerford: aquatic hemiptera. 97 



ready for action, and then quite suddenly she decided the task too much 

 for her frail limbs and their unsteady support upon the water, and 

 turned away. 



In the laboratory with a movable armed binocular the bugs can be 

 watched most satisfactorily. The notes of a few observations are given 

 here. In one case a third instar nymph was watched as it caught an 

 Ostracod resting at surface film. The nymph stalked slowly up to the 

 prey, its body all aquiver and weaving from side to side. The tips of 

 its antennae were turned down to the surface. The beak directed down and 

 slightly forward. When close to the Ostracod a sudden move and the little 

 Entomostracean was caught and carried away upon the tip of the beak. 

 It was kept free from the supporting surface. Under the binocular the 

 stylets could be seen playing about in the body of the victim, darting and 

 bending around as if to ream out every available bit of nutriment. One 

 half of the tip segment of the beak was pressed between the valves near 

 their hinge. The movements of the stylets were also splendidly shown 

 one time when an adult female bug caught a mosquito wriggler. The 

 wriggler came to surface for air a centimeter away. This excited the 

 marsh-treader greatly. She turned her antennae to the water surface, 

 and cautiously advanced until the position of the wriggler was located. 

 The beak was then let down slowly into the water and turned forward, 

 imperceptibly approaching the respiratory tube of the larva. All at once 

 a tiny thrust was followed by a sudden but brief struggle of the har- 

 pooned wriggler. It was as effectively caught as a fish upon a spear. 

 Five minutes later the wriggler still had a little life. The beak of the bug 

 was inserted near the base of the respiratory tube. The stylets are 

 capable of tremendous exertion. When the tip of the beak has found its 

 prey, the slender flexible stylets are let out at unbelievable lengths in a 

 search for a vulnerable place in the chitinous armor of the mosquito larva. 

 The long head of Hydrometra is necessary to accommodate the play of such 

 long spears. As noted above, the bugs as soon as hatched become com- 

 petitors, and captors as well, of their fellows. Often a chain of two or 

 three little dead fellows each with his beak in the next one, has been ob- 

 served, a silent testimony to the fact that while one nymph was interested 

 in feeding upon a new-born brother, his own happiness was ended by an 

 attack from behind. 



DESCRIPTION OF STAGES. 



The egg has been splendidly figured by Martin, but our own figure 

 was made before we discovered the drawing by Martin. 



Size. Length, 2.07 mm.; greatest diameter, .277 mm. 



Shape. Very long and spindle shaped. The slender stem at the base 

 of the egg set into a little button-like pad attached to the support. 



Color. Brown. The spindle-shaped ends lighter than the body. 

 Markings consist of longitudinal flutings over the body of the egg and 

 lacings at the end, as shown in the drawing on plate XIII. One-fourth of 

 the total length at each end is taken up by this lacing. This leaves 

 one-half the entire length of the egg covered by the flutings. The entire 

 surface is punctate. 



7 — Sci. Bui. — 1669. 



