on 
N 
STUDIES ON PERILLUS BIOCULATUS FAB. 
laid about June 10. But one of the females that laid eggs early in June 
also laid eggs as late as July 12. Thus the last eggs laid could not be 
expected to produce adults of the first brood before August 6, and 
the second generation adults by September 8 or 9. In western New 
York, during 1914, three broods of Perillus were reared when the 
overwintering females deposited their eggs before June 25, but the 
same females continued to lay eggs after that date, and these later eggs 
produced only two broods of bugs before the fall frosts drove beetle 
and bug into hibernation. 
In the latter part of September and early October, depending much 
on the arrival of killing frosts, Perillus begins to seek hibernation 
quarters. The bugs usually hide away under piles of leaves or rubbish, 
altho many of them are found entering buildings. In fact, the habit 
of entering buildings appears to be an important factor in the pres- 
ervation of the species in northern localities. 
Egg cluster. The eggs are normally deposited in a compact double 
row (PI. I) on the upper surface of the potato leaf. Two egg masses 
have been found on squash leaves, but on vines that were growing by 
the side of a potato patch, thus they were probably accidental. It is 
unusual to find eggs arranged in other than a double row, but when 
disturbed the female bug may at times deposit an irregular mass. In 
such case a partial third row of eggs is usually formed. Irregular egg 
masses usually occur where the female has been forced to lay on small, 
newly formed potato leaves. The average number of eggs laid in one 
mass is estimated at 14, altho 24 and 26 eggs have been found in single 
clusters, and one mass that was certainly unusual contained 33 eggs. 
The large egg masses are usually laid following times when the female 
goes three or four days without laying. 
Oviposition. The overwintering bugs begin laying eggs in June, 
very soon after the potato beetles make their appearance on the potato 
leaves. The writer has observed the process of egg laying many times, 
both in the field and in the breeding jars. When the female deposits 
an egg, the tip of the abdomen first feels for the proper place, and 
while the valves of the ovipositor are pressed close to the leaf surface, 
they may be observed to swell and spread as the egg moves into posi- 
tion. With the end of the egg placed firmly against the leaf surface, 
the valves are moved upward and away, thus uncovering the egg 
and leaving it standing on end in the desired position. The actual 
movement of laying an egg requires only ten or twelve seconds. The 
interval between deposition of eggs is usually from one and one-half 
to two minutes, but the time for an individual bug rarely varies but 
