INSECT ENEMIES OF EASTERN FORESTS 449 
of many of the characters. In some cases, therefore, it may be neces- 
sary to study a large series of specimens and to utilize every available 
character of structure in addition to data on the biology and host 
relationships in order to determine the species accurately. 
The larvae of the various species differ considerably in habits. Here 
are found leaf rollers, some living in a tube of silk mixed with frass or 
in a silken case within a folded leaf or leaves; others ave borers in 
shoots, in the bark of trees, in roots, cones, or fruits, some feed on 
stored food, and a few are predaceous on coccids. 
About 25 species of Acrobasis are known to occur in the eastern part 
of the United States, and their identification is difficult. Most of them 
are bud or leaf feeders. 
The moth of the pecan 
leaf casebearer (Acroba- 
sis juglandis (LeB.)) is 
dark mouse gray, with the 
head, thorax, and base of 
wings grayish to white. 
The wing expanse is about 
34 inch. The forewings 
are blackish at the middle 
of the costa, with an ante- 
medial reddish area 
toward the inner margin. 
The hind wings are ashy- 
gray. The full-grown 
larva is about 5g inch long. 
The head and legs are 
black and the body olive 
green (Gill, 783). This 
species is distributed from 
Ontario to Florida and 
Texas. The larvae feed on 
various species of hickory 
and walnut. The moths 
emerge from late in May 
through July. The young 
larvae feed thr oughout the 
summer on the lower epl- 
dermis of the leaves, and 
each hibernates in a small FIGURE arvae of the pecan leaf casebearer 
case constructed on a bud eee juglandis) in their cases, and injury 
or twig. In the spring done to pecan leaflets. 
they eat into the buds, m1- 
erate to other buds and construct new cases when necessary, and finally 
finish their feeding upon the foliage. The case is attached to a stem 
at one end, the other being open so that the larva can crawl out to 
feed. Although the amount of foliage consumed is not great, the 
larvae often eat into the stems of the compound leaves, causing them 
to break off (fig. 99). This, together with the bud 1 injury, is sometimes 
very serious (Moznette air All 309). 
The moths of the pecan nut casebearer (Acrobasis caryae 
(Grote) ) are rather dark gray, with a ridge or tuft of long dark scales 
