70 Wisconsin Academy of Sciences, Arts and Letters. 
revealed to us that some of the eggs had been washed out of 
the injured receptacles. A number of leaves with these in¬ 
jured receptacles were taken out of the rain and most of 
them hatched by five o’clock in the afternoon. The next morn¬ 
ing we again visited the trees and found that many of the eggs 
contained within the injured receptacles had hatched. An¬ 
other observation might be mentioned which may explain the 
cause of the destruction of some of the eggs. Occasionally a 
small red mite was noticed within a broken receptacle busily 
engaged with the egg, but whether or not these mites injured 
the eggs the observations thus far made did not determine. 
Within five parasitized eggs we found on an average twenty- 
two pupae of Trichogramma pretiosa , although as many as 
thirty and sometimes only fifteen were found. The number 
of pupae within each parasitized egg was, respectively, 15, 18, 
22, 25 and 30. 
The color of an egg, which contains full-grown larvae or 
pupae, is black (Fig. 1 , p). This color persists very distinctly, 
even after the parasites have emerged, and always serves to 
distinguish a parasitized egg. The parasite escapes by cut¬ 
ting a round, jagged hole through the shell of the host egg and 
epidermis of the receptacle. These exit; holes are rather 
numerous, the insect in all cases thus far examined cutting its 
way through the lower epidermis of the receptacle and not 
through the upper epidermis. We have, as yet, not found a 
single parasitized egg below the upper epidermis, and it would 
be interesting to know through which side of the leaf the para¬ 
site bores out, if such cases occur. Quaintance and Brues (8) 
find in the case of the cotton boll w T orm that, “although several 
parasites ( Trichogramma pretiosa Biley) may come from a 
single egg, generally but one exit hole is present, it being in 
most cases on one side.” When the parasite emerges, it often 
leaves whitish specks of excrement on that part of the lower 
epidermis, which covers the blackened host egg. 
DEVELOPMENT OF THE EGGS. 
When the egg is first deposited above the lower epidermis, 
it is discovered from the upper side of the leaf only with great 
