196 SPAN-WORMS. 
pea-green. The rudimentary hind-wings reach to the back 
part of the first abdominal segment; the fore-wings to the 
middle of the same segment. The exerted ovipositor con- 
sists of two joints, the last third of the posterior one having 
the hairs perpendicular to the joint. Both sexes are shown 
in Fig. 194. 
The pupa is dark brown, coarsely punctured, the 
divisions between the abdominal segments finely so; the last 
segment is conical, smooth at the end, and tipped with two 
short, stout, divergent bristles. 
The caterpillars are found on the apple, rose, blackberry, 
elm and other plants, and have thus far never become 
numerous enough to cause injury. They are about an inch 
long, dark-brown or dusky reddish-brown with dirty white 
or gray dorsal and dirty yellow lateral lines. They reach 
their full size in June, when they enter the ground for pupa- 
tion and hibernation. 
CANKER-WORMS. 
There are two kinds of canker-worms which are known 
to be very destructive to the orchards, especially to the 
apple-trees. A third species is found in the northern 
portion of our state, sometimes in such immense numbers as 
to defoliate large tracts of forest-trees. It has thus far not 
been found upon fruit trees, but prefers the linden, ash and 
elm, but when very numerous no foliage escapes its voraci- 
ous appetite, and the caterpillars pass through the forests 
like a devastating fire. They hatch very early in the season, 
and perforate the leaf-buds, thus causing much more 
damage than if they would simply eat the unfolded leaves. 
As no males have been raised thus far this third species re- 
mains undescribed; the females are wingless and deposit 
their numerous eggs in perfect rings around a small twig, in 
this respect resembling the tent-caterpillars. 
