INSECT PESTS OF OHIO SHADE AND FOREST TREES 207 



The present publication embraces only the more important 

 shade-tree insects that are likely to be of greatest economic sig- 

 nificance. They are grouped in classes according to the manner of 

 feeding. It is suggested that, if any difficulty is encountered in 

 identifying a given depredator, the host index in the back of the 

 publication be consulted freely, where there will be found the vari- 

 ous insect pests listed under both the common and the technical 

 name of the host. 



LEAF OR FOLIAGE-DESTROYING INSECTS 



It may safely be asserted that among the leaf or foliage de- 

 stroymg insects are found our most destructive shade and forest 

 pests. Many not only are voracious, but are almost omnivorous in 

 their feeding habits and in addition multiply very rapidly. 



THE WHITE-MARKED TUSSOCK MOTH 



(Hemerocainjia leucostigma S. & A.) 



Description. — The white-marked tussock moth is best known 

 in the larval stage, the striking markings of which have given it 

 its common name. The full-grown larva is a gorgeous creature 

 about an inch and a half in length, with four dense white tussocks, 

 or brushes, of hair on its back. Just behind these are two shiny 

 red warts. The head is brilliant coral-red with a fringe of white 

 hairs arising from the cervical shield and extending over it from 

 above. Arising on each side and just back of the head is a pencil 

 of black plumes about a half-inch long. A similar single pencil 

 arises from the rear of the body. A broad, black band extends 

 almost the entire length of the back and this is bordered by a yellow 

 band on each side. The yellow bands are bordered with dark gray, 

 and through the spiracles extends a thin black stripe. The cater- 

 pillar is yellow beneath. Clusters of white bristles arise from the 

 sides of the body with a brilliant black bristle occasionally inter- 

 mingled. (See Plate XVII, Fig. 1 and insert in Fig. 2.) 



The newly-hatched caterpillar is pale in color, sometimes tinged 

 with yellow, and clothed with long, variable hairs. Upon becoming 

 full grown, the caterpillar seeks some sheltered position, if such is 

 available, and spins a silken cocoon, in which are interwoven the 

 hairs of the body. Abrasions or cracks in the trunk of the tree ; 

 cracks and crevices of nearby walls and fences ; crannies in porches 

 and the sheltering ledge of weatherboarding on dwellings, are ex- 

 amples of the sites chosen by the caterpillar for cocoon spinning. 

 Sometimes the cocoons occur in great masses, as indicated by Plate 

 XVII, Fig. 2. Frequently, however, when sheltered spots are not 



