1890 .] 
519 
[Packard. 
scription of the fourth stage of Datana integerrima. The food plant 
is the walnut. As is well known, these larvae feed in large conspic- 
uous clusters, being social through larval life. 
First stage. — Length, when 24 hours old, 5 mm., July 24. In 
this larva the head is verjr large, entirely black and hairy, being 
nearly twice as wide as the end of the body. The body is brick- 
red, with a faint subdorsal and lateral yellowish stripe along the 
body, and a diffuse spiracular yellowish line. There is a distinct 
small, black prothoracic shield, transversely oblong, from which 
arise about twenty black hairs, slightly clavate, two or three of 
them as long as the segment is thick. A distinct, black suranal 
plate is present ; it is entire and rather large, though not so wide 
as the tenth abdominal segment. The piliferous warts are minute, 
and the dorsal and lateral glandular hairs arising from them are 
more or less club-shaped, some of them markedly so, and not quite 
so long as the body is thick. The thoracic legs are black ; the 
middle abdominal legs are concolorous with the body ; the plantse 
dusky ; the anal legs are about half as thick as the others, and 
black at the end. 
In another specimen of this stage, of the same length, which is 
just about exuviating (July 23), the body being very long and the 
head small in proportion to the body, the suranal plate is divided 
into two oval lanceolate black plates, the small ends pointing tow- 
ards the head. Otherwise the body is marked as in the above 
described specimen, except that there are black spots at the base of 
the middle abdominal legs. The hairs are not represented as so 
clavate as in the other specimen. It is possible that the latter is 
in the second stage, but if so, the suranal plate would not probably 
be so large and entire. 
Third stage. — Length, 7 mm. (probably not of the normal 
length, owing to confinement), July 30. About ready to moult, as 
the prothoracic segment is somewhat swollen. The black protho- 
racic plate still persists, and the hairs arising from it are about 
twice as long as those elsewhere, but the black suranal plate has dis- 
appeared ; the anal legs are still slight, and the body beyond the 
sixth abdominal segment is upraised. The reddish color has deep- 
ened, and the yellowish lines are more distinct, while the spiracular 
line, enclosing the distinct black spiracles, is pale lilac ; the middle 
abdominal legs do not appear to be spotted. 
Fourth stage. — Length, 10 mm., August 13 (evidently under- 
