INSECT ENEMIES OF EASTERN FORESTS 215 
larger than those of the other two species, and the coloration in solid 
reddish brown without spots on the elytra, and the head and thorax 
are green without pale sides. The larvae of all species are black when 
young and change to a dirty yellow with age, are very similar in 
appearance, and are difficult to distinguish. 
Several species of the genus Calligrapha are rather common on the 
foliage of broadleaved trees, but C. bigsbyana (Kby.) is the only one 
that is at all important. This medium-sized, light-brown to straw- 
colored beetle, ornamented with variously shaped bronze or greenish 
markings, is often very abundant on willows in the Northeastern 
States, causing complete defoliation over wide areas. 
The adult of the elm leaf beetle (Galerucella wxanthomelaena 
(Schr.)) (fig. 58, B) is yellowish to dull green in general color with 
a black stripe, sometimes indistinct, along the sides of the elytra, and 
isabout 5mm. long. The antennae and the legs are yellowish, the eyes 
are black, and there are black spots on the head and thorax. The eggs 
are orange yellow, and the larvae are yellow spotted with black. When 
full grown, they are about 10 mm. in length. The pupa is orange 
yellow to golden yellow, and approximately the same size as the adult. 
(See Britton, 55 and Readio, 360.) 
This beetle was introduced from Europe about 110 years ago, and 
was first collected at Baltimore, Md. It is now well established over 
most of the United States. Al the elms are attacked, and though the 
European species are usually the most injured, the American elm is 
also severely damaged. 
The elm beetles hibernate in the adult stage in sheltered, dry places, 
such as barn lofts, sheds, attics, and stone walls. They become active 
when the buds begin to swell in the spring, and feed on the developing 
foliage. The females deposit their eggs in groups of 5 to 25 on the 
lower surface of the leaves. Oviposition begins late in May and lasts 
for several weeks, during which time each female lays from 400 to 800 
eggs. These hatch in about a week, and the larvae feed on the under 
side of the leaves until full grown. They then crawl away to pupate 
in crevices in the bark on the bole or larger branches, or at the base 
of the tree. The larval period lasts from 2 weeks to a month and the 
pupal period about 10 days. The new adults emerge and lay eggs. 
There may be one or two complete generations in the Northeast, ce- 
pending on the locality and weather conditions. Farther south the 
longer growing season may permit at least a partial third generation. 
Most of the damage is done by the larvae of the first generation. 
Under forest conditions in this country, the elm leaf beetle is not 
a serious pest, but it is of very great importance asa defoliator of shade 
and ornamental trees. It can be controlled under these conditions very 
easily by sprays (p. 52) applied to the lower surface of the leaves. 
Usualiy one spraying operation during the flight of the first genera- 
tion is sufficient, but in some cases 1t may be necessary to spray again 
when the second generation is hatching. It is also advisable to take 
advantage of the mass hibernating habit of congregating im attics and 
belfries of old buildings, and trap and destroy them during the fall 
and winter. Two species of European. parasites have been liberated 
in various parts of the country, but there have not been any recoveries. 
According to Berry (28), a native species, Zetrastichus brevistigma 
Gahan, is at times a very effective pupal parasite. 
