630 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
and is therefore very fragile. It is brownish and the enveloping lay- 
ers are made up of small ‘overlapping shell-lke portions. Wasps are 
largely predaceous in habit, and their larvae feed on other insects. 
Adult’ wasps are very partial to nectar, ripe fruits, and honeydew, and 
feed this diet to young larvae for a short time. At times they injure 
fruits, and may often be a considerable nuisance, but on the whole 
they are beneficial, because they are scavengers and help reduce the 
numbers of injurious insects. 
A number of species of Vespula are difficult to distinguish from one 
another. They are the small, black and yellow wasps, commonly 
FIGuRE 193.—Nest of the common yellow jacket (Vespula diabolica (Sauss.) ): 
A, Side view; B, same with section of shell removed to show interior. (Cour- 
tesy Conn. Agr. Expt. Sta.) 
known as yellow jackets or hornets, which nest in or above the ground. 
The bald-faced hornet (V. maculata (1.)) is the common white- 
faced hornet, which usually attaches its nest to trees or bushes. 
The giant hornet (Vespa crabro L.) 1s our largest species, about an 
inch long. It builds its nest in hollow trees, or suspends it from the 
roof within buildings. It is found in the East, particularly in New 
York and Connecticut, and occasionally attracts notice by the removal 
of bark from the stems of lilac, ornamental box, birch, and other 
shrubs. The hornets appear to feed on the sap flowing from the 
wounds, and they use the bark tissues in the construction of “their nests. 
They tear the bark away down to the camoium, and the injury fre- 
quently results in nearly girdling the stems. On account of the in- 
sectivorous habits of wasps, they should not be destroyed unless they 
are in places where they are likely to be disturbed, or unless they are 
injuring trees and shrubs. 
The following control measures are recommended : * 
When it is necessary to deal with large nests of hornets it is desirable to destroy 
the entire colony. In the case of nests in buildings or trees, this can be done by 
carefully observing the nest in the daytime, then at night plugging the entrance 
holes with cotton soaked in chloroform or benzol. A box or garbage can con- 
taining an additional wad of cotton soaked in the anesthetic is next put up so 
as to enclose the nest, which is then cut down with a long-bladed knife. A tight 
cover should be applied to the container immediately after the nest has dropped 
into it, so as to destroy the entire colony. 
7 THE DESTRUCTION OF WASPS AND YELLOW JACKETS OR HORNETS. U.S. Bur. Ent. 
and Plant Quar. E-338, 2 pp. 1935. [Processed. ] 
