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HUNGERFORD: AQUATIC HEMIPTERA. 145 
it is laid, swells considerably as the embryo develops within. In fact 
Bueno has noted that it gains one-half of its first length. 
Hatching. The hatching process is an interesting one, and easily 
observed. A figure on Plate XVII shows the process at its beginning. A 
rent, transverse to the long axis of the egg, takes place near the 
micropylar end of the shell. The cap thus formed is gradually pushed off 
and the bug by successive heaves comes forth. When part way out, the 
fore limbs can be seen bound and outstretched upon the venter. When 
the bug is nearly out of the shell it gives a backward heave. The mem- 
brane breaks, and as it gradually slips back, the fore limbs are freed and 
snap into normal position (femora outspread and tibiz appressed). 
Shortly the whole animal is free and rights itself in the water, soon 
swimming out to some support. The whole process may be completed in 
four minutes. 
Behavior of Newly Hatched. The little nymphs have a tendency to 
cluster together—clump themselves together at the surface. They are 
ready to strike for food as soon as their exoskeletons harden. The hatch- 
ing of a given batch of eggs may last for a day or two before the male 
frees himself from the egg mass. In this case the older, darker nymphs 
feed upon the more feeble freshly hatched. 
Number of Instars. There are five nymphal instars. The total period 
required for development from deposition of egg to adult was recorded 
by Bueno for 3 individuals which took 43, 53 and 54 days respectively. 
The various stages take about a week each, with a longer time for the 
5th instar as a rule. One brood, hatched May 21, went into 2nd instar 
May 26, into 3rd instar May 31, into 4th instar June 6, into 5th instar 
June 15, and adult June 25, making 5 days for the first, and 10 days 
for the last nymphal instar, making with the six-day egg stage, a total 
of 40 days. 
Fecundity. Egg-laden males may be taken throughout the warmer 
part of the year. Bueno has found them in New York from middle of 
May to the end of August. Here in Kansas they have been taken both 
earlier and later. The female doubtless lays several batches in the course 
of the season, each batch, as indicated by the counts on the males, rang- 
ing from 65 to 159 eggs. Miss Slater said she found from 75 to 85, but 
in Kansas specimens it was not uncommon to find as many as 150 eggs 
_ on the back of the male. 
Longevity. These insects are long lived, living for more than a full 
year at least. 
Food Habits. The nymphs have been fed in the laboratory upon 
mosquito wrigglers, Corixids and like forms. The literature contains 
a long list of the food organisms from fish to snails. Professor Todd, 
in 1883, published a note in American Naturalist about a Belostoma 
%-inch long that vanquished a fish three or four times its own length, 
which was like a dace in form. 
Behavior. We are indebted to Severin & Severin for notes on the be- 
havior of these bugs. They found them positively thigmotactic. As to 
10—Sci. Bul.—1669 
