4 BULLETIN 598, U. S. DEPARTMENT OF Sag ou 
larva is at rest covers the head. The spreading aide tufts give the larva & 
depressed appearance, - 
First instar (Pl. II, fig. 1).—Width of head, 0.46 to 0.50 mm; total length, 
1.5 mm.; when full fed, 3 mm. The head is shining black and is much wider 
than the thorax of a newly hatched larva. The body is cylindrical, pale green- 
ish white, and marked with black setiferous tubercles. Dorsally the tubercles 
appear as follows: On the first thoracic segment, a large dorsal plate and two 
very small tubercles on either side; second thoracic segment, one large coni- 
pound tubercle on either side near the cephalic margin and a very small me- 
dian tubercle near the caudal margin; third thoracic segment, 2 conspicuous 
tubercles on either side; first to eighth abdominal segments, 3 conspicuous 
tubercles on either side arranged in a triangle, two of them being near the 
cephalic and one near the caudal margin; ninth abdominal segment, 1 large 
compound tubercle on each side; tenth abdominal segment, 1 large plate cover- 
ing most of the dorsal aspect of the segment. On all the thoracic segments and 
on third to ninth abdominal segments there are 3 small tubercles on each 
side; on abdominal segments 1 and 2 there are 4 on each side; and on ab- 
dominal segment 10 there is 1 one each side. All the lateral tubercles and 
lateral-dorsal tubercles bear 1 white seta. Black sets are all dorsal, 4 arising 
from each thoracie segment, 1 from each of the 4 median abdominal tubercles, 
and 6 from the anal plate. 
Second instar.—Width of head, 0.65 mm.; total length, 5 to 6 mm. when full 
fed. This instar differs chiefly from the preceding in the abundance of long 
whitish hairs which arise in considerable numbers from all the tubercles. The 
tubercles*are larger and contrast strikingly with the color of the body. 
' Third instar—Width of head from 1.12 to 1.16 mm.; total length, 10 mini. 
when full fed. More hairy than the preceding instar. , ; 
Fourth instar (Pl. II, fig. 2).—Width of head, 1.7 mm.; total length, 13 to 
14 mm. The dorsal tubercles are meek obscured by the hair arising from 
them. 
Fifth instar.—Width of head, from 1.88 to 2.19 mm., average 2.1 mm.; total 
length, 18 to 19 mm. Tufts at sides of each body segment becoming connie 
ous. and the black pencils may appear in this instar. j 
‘Sixth instar—Width of head, from 2.91 to 3.09 mm., average 3.0 mm.; 
total length when full fed. 22 to 25 mm. The side tufts have become so con- 
spicuous that they give the larva an almost flattened appearance. The black 
dorsal tufts are not yet touching and do not yet form a conspicuous crest. 
Seventh instar (Pl. Il. fig. 3).— Width of head, from 3.43 to 3.52 mm., average 
3.46 mm.; total length, 27 to 32 mm. Practically the same as the preceding. 
Highth instar.—Width of head, from 4.10 to 4.80 mm., average 4.2 mm.; 
tétal length, 32 to-40 mm. This larva is very much like the preceding if it 
has yet to pass through another instar, or if this instar is the last it is like 
the mature larva previously described. : 
Ninth instar (P1. 1).—Width of head, from AT to 4.9 mm., “ay erage 4.8 mm.; 
total length, 35 to 42 mm. This instar differs conspicuously from the imina- 
ture for ms because of the striking black crest. 
COCOON. 
(Pl. ITI, fig. 3.) 
The cocoon is usually ellipsoidal, sometimes slightly flattened on one side, 
depending on the material which surrounds it. In length it averages 23 mm. 
and in width 15 mm. The lar val mixes most of its gray hairs into the silk, 
making the cocoon very hairy. ‘In color it is dirty gray. 
