REPORT OF THE STATE ENTOMOLOGIST 1918 3I 
stage lasts about 8 days. About 59 days are required for the life 
cycle of the second generation. The biological data given above is 
based largely upon the work of Mr Caffrey and his associates at 
the Arlington (Mass.) Laboratory. 
Available data indicate a connection between the percentage of 
stubble infested and the stalk infestation and, generally speaking, 
if the stalk infestation is below ro per cent or thereabouts, the 
stubble infestation may be less than 1 per cent; while over 30 per 
cent stalk infestation may result in nearly 14 per cent of the stub- 
ble being infested, especially if the latter is long, while badly 
infested fields having a stalk infestation of 70 per cent or more 
may have nearly 60 per cent of the stubble inhabited by borers. 
Description. The female moth is pale yellow with a robust body 
and a wing expanse of a little over aninch. The outer third of the 
fore wing is marked by two darker serrate lines. The hind wings 
are a plain yellow. The male is reddish brown and has a long, 
slender body. It is slightly smaller and much darker than the female. 
There is in this sex a pale yellow streak between the two serrate lines 
on the fore wings and two small yellowish spots near the middle. 
The hind wings are grayish with a broad band of pale yellow. 
The nearly full-grown, overwintering caterpillars are about 
three-fourths of an inch 
in length, yellowish gray, 
brown headed, the body 
minutely brown spotted and 
with indistinct longitudinal 
reddish or dusky stripes. 
They may be distinguished 
from most other corn borers 
by the series of well-de- 
veloped, horny, light brown 
tubercles, each with one or 
more short, stout hairs. The 
arrangement of the tubercles 
on the posterior extremity 
is shown in figure 2. These 
are the only caterpillars 
which feed upon the de- 
Fig. 2. Posterior extremity of a veloping tassels, bore in all 
corn borer from above, showing portions of the stem and 
tubercles, or warts, and hairs cob andy dageunn eemeren 
upon the cob. (See page 61 for characteristics of other corn 
insects.) 

