114 
THE GIPSY MOTH. 
which is marked with yellow, is a double row of five pairs 
of blue spots, followed by a double row of six pairs of red 
spots. This double row of spots may almost invariably be 
seen very distinctly on the back of a caterpillar which has 
attained a length of one inch and a half or more. No other 
New England larva has this double row of blue and red 
spots along its back. The mature gipsy moth caterpillar 
not infrequently 
attains a length 
of three inches. 
The caterpillars 
become full 
grown during 
July, mostly 
about the first. 
Injury done by 
the pest is, there- 
fore, largely con- 
fined to the 
months of May 
and June, being 
most serious as 
the caterpillars 
become grown. 
The Pup a. — 
When fully 
grown, usually 
in July, the Cat- 
erpillar spins a few threads of silk as a supporting frame- 
work, casts its skin and changes into a pupa, or, as it 
is sometimes called, a chrysalis. The pupa is dark reddish 
or chocolate in color and very thinly sprinkled with light 
reddish hairs. Unfortunately, it resembles the pupae of 
certain other moths found in Massachusetts (and New Eng- 
land), and cannot, unless by experts, be identified at a 
glance. The thinly sprinkled, light reddish hairs are, how- 
ever, characteristic. The pupa stage lasts from ten days to 
Fig. 7.— Male and Female Gipsy Moths. Natural 
size. (After Forbush and Fernald.) 
