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! 
: 
1894,] The White-Marked Tussock Moth. 397 
with other characteristics which it possesses, are attractive to 
the entomologist. Natural selection has favored the structure 
of the legs, the feathery antenne, the subdued ashy-gray 
color, all to one purpose; to lend in blending its form with 
the natural environment on the bark of trees. In fact we find 
ma) 
Sri 
A 
ta 
y rog 
sa ht N 
BIEN ie 
pista 
a os ay 
oe 
Fig. 1. White-marked Tussock-moth: æ, female moth on cocoon; 4, young larva 
hanging by thread; c, female pupa; d, male pupa; ¢, male moth. [After Riley]. 
the caterpillar favored by its very conspicuousness, while 
nature is effecting good to the same species on a diametrically 
different line by so modifying the form of the male moth as 
to deceive its enemies from seeing it. Parasitism may be 
looked upon as a recent enemy—for nature is strangely 
unable to cope against their invasion. The female pupa 
within a frail cocoon may be pierced with ease by the oviposi- 
tor of a Hymenopterous parasite and is obliged to give up her 
life’s juices in hopeless submissson to the offspring of the par- 
asite hatching within her body. Along these lines we are to 
look forward for a means of extermination. On September 
30, 1898, the tree trunks along the streets in the locality above 
named, were examined with. a view of learning some further 
facts about Orgyia. A number of cocoons were found as the 
result of the search, all being near the ground. These were 
taken home to my study, where on opening them, they proved 
to be quite old, of a dirty color, and many were deserted. On 
two of the cocoons there were plastered masses of small white 
eggs made adherent by some glistening tenacious frothy sub- 
stance which had become hardened on drying. Inside of 
others were empty pupas and cast off skins. Some Hymenop- 
terous parasites had hatched and lived in the old pupa husks, 
which later had made their exit through an irregular hole cut 
