582 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
The full-grown larva 
of the butternut woolly 
worm  (Slennocampa 
caryae (North.)) is 34 
meh, jin lene thee dsine 
body is covered with 
flocculent white tufts, 
which rub off on being 
touched, and the naked 
larva is then green, dark- 
est on the top, and with 
indistinct blackish spots 
on the sides. The head 
is white with black eye 
spots. This species oc- 
curs throughout the 
Northeastern States and 
in the southern parts of 
Ontario, New Bruns- 
wick, and Quebec, Can- 
ada. The larvae feed 
eregariously on the foli- 
age of butternut, black 
walnut, and hickory in 
July and August, and 
occasionally they cause 
considerable defoliation 
locally. The cocoon is 
: formed in the ground 
oe and is composed of par- 
' ticles of earth and sand 
FicurE 168.—The brown-headed ash sawfly cemented together. As 
(ZVomostethus multicinctus) : A, Adult female; far as is known, there is 
B, adult male; C, larvae. : 
one generation annually 
and the winter is passed in the cocoon stage. 
There are many species in the genus Periclista, and those whose 
biology is known feed on the foliage of hickory or oak. Several 
species are usually common in the Northeastern States. The larv 
of some species are sometimes abundant enough locally to cause the 
fohage to appear ragged. In general, the larvae are about I to %4 
inch in length when “fully erown. The head in some species is pale 
green; 1n others, black with a pale face or entirely black. The body 
is usually leaf green, although in some species the back is grayish, and 
sach is armed with rows of small black, green, or white ‘single, two- 
pointed spines, some being V- or Y-shaped. The first thoracic : segment 
immediatey back of the head is usually fringed with spines. Per?- 
clista caryicolum (Dyar) and P. hicoriae Roh. feed on hickory, 
P. diluta (Cress.) on white oak and swamp white oak, P. purpuri- 
dorsum Dyar on red oak and white oak, P. guercus Roh. on black oak, 
scrub oak, and white oak, and P. simé/aris Roh. on white oak and 
scarlet oak. Each of these species has one generation annually. The 
adults emerge late in April or early in May and the larvae are active 
C 
