4 
146 THE UNIVERSITY SCIENCE BULLETIN. 
food reaction Belostoma rests obliquely in the water. If hungry, they 
respond to any impact in the water and will, on occasion, employ all 
their limbs to hold some obstreperous prey. 
DESCRIPTION OF STAGES. 
Egg Stage. 
Size. 2.66 mm. long; .9 mm. in widest diameter. 
Color. Silvery gray, the top appearing darker to the unaided eye, 
and opaque white through the binocular. A brownish spot appears to 
one side of the top. This is the micropylar area. An irregular tracery 
of hexagonal figures can be discerned upon careful scrutiny. 
Shape. The general shape is best shown by the drawing on plate XVII. 
It is an elongate cylindrical form, rounded on anterior end, more pointed 
on posterior. The eggs and egg masses often appear grey and fuzzy, 
due to colonies of Epistyllis and Vorticella. The pointed end of the egg 
is set into a transparent gelatinous plate. This plate can be removed 
from the bug, carrying all the eggs with it. It is pliable when fresh 
and looks like a sheet of agar-agar. 
First Instar. 
Size. Total length, 4.6 mm.; greatest width across abdomen, 2.35 
mm. The other measurements are shown in the chart with those of the 
other instars below. 
Color. Dorsum: brown, thorax with a few lighter markings and ab- 
domen decorated with light areas in 6 rows. The marginal spots large 
and rectangular. There is a faint series of median dots on the abdo- 
men, which is extended forward across the thorax and head as a slender 
light line. 
Venter. Smoky brown, barred with pale yellow. The eyes dark red; 
fore femora barred; fore tibiz# with 2 broad yellow bands. All the 
femora bear 2 yellow bands and the remaining tibiz 2 yellow bands. 
Shape Much as in adult. Relative distance between the eyes greater. 
Structural Peculiarities. The tarsi are all 1-segmented and armed 
with two claws each. Bueno says the antenne are short club-shaped, and ~ 
1-segmented, about 114 times as broad at the base as at the apex, and 
twice as long as the greatest diameter. The ventral portion of the abdo- 
men is densely clothed with minute hairs, the metasternal shield present 
but not relatively as large as in the older forms. Spiracles evident, 
caudal pair much larger and guarded by hairs in such a manner as to 
provide a channel to margin of abdomen. 
Second Instar. . 
Size. Length, 5.75 mm. to 7 mm.; width, 3.2. Other measurements 
on chart. 
Color. The pattern about as in first instar, but general color much 
lighter, the dark brown of first instar being replaced by a lighter green- 
ish brown, with the bars reaching the lateral margins more pronounced, 
due to a darker smoky coloring. The ventral aspect much lighter than 
in the first instar. 
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