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 antennz 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 antenne 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- 
q 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 
ig of the egg set into a little button-like pad attached to the support. 
a 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 piate XIII. One-fourth of 
i 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. 
{—Sci. Bul.—1669. 
