COURTESY CONN. AGR. EXPT. STA. 
FIGURE 193.—Petiole of maple leaf severed by larvae of the 
maple petiole borer, Caulocampus acericaulis. 
tree in a week. Shade trees are especially subject to serious de- 
foliation (448). 
The black-headed ash sawfly, Tethida cordigera (Beauvois), oc- 
curs throughout much the same area as the brown-headed ash 
sawfly. The habits, food plants, and life histories of the two spe- 
cies are also very similar. Full-grown larvae are whitish with a 
yellowish tinge and are about 18 mm. long. The head is shiny 
black, and the thoracic legs are blackish-brown. This species is 
occasionally a pest of shade trees. 
Eriocampa juglandis (Fitch) (previously misidentified as 
Blennocampa caryae (Norton), the butternut woolly worm, occurs 
in southern Canada and throughout the Northeastern States. Its 
hosts are butternut, black walnut, and hickory. Full-grown larvae 
are green, with indistinct black spots on the sides and are about 
18 mm. long. The body is covered with flocculent white tufts 
which rub off when touched, and the head is white with black eye 
spots. The larvae feed gregariously, often causing considerable 
defoliation locally. When they become full grown they move to 
and enter the ground, where they form cocoons composed of par- 
ticles of sand and earth cemented together. Winter is spent in 
the cocoons and there is one generation per year. 
The genus Hoplocampa Hartig is represented in eastern Amer- 
ica by a number of species, all of which presumably feed as lar- 
vae in the fruit of their hosts. Eggs are laid in the calyx of 
flowers and the larvae bore into and hollow out the developing 
fruit. Some of the eastern species and their known hosts are as 
follows: H. oskina Ross—hawthorn in the Central States, H. 
464 
