INSECT PESTS OF OHIO SHADE AND FOREST THEES 255 



sometimes plentifully distributed on other than fruit trees, and 

 hence is treated in the present grouping. 



Description T.he full-grown caterpillars (see Plate XXXVIII, 

 'ig. 3) measure an inch or more in length. On the fourth segment 

 >f the body, also called the first abdominal segment, there is a con- 

 spicuous red hump. The head is coral red and the body is marked 

 with black and yellowish to white lines. Black, stout spines in a 

 double row adorn the top of the body and smaller spines are found 

 lower down along the sides. 



The pupa is short, stout and a bright glossy brown, occurring 

 in a slight cocoon in trash on the ground. 



The adult is an inconspicuous, grayish brown moth, the female 

 having a wing expanse of about 1% inches and the male slightly 

 less. The eggs are white, nearly round and are deposited in masses 

 of a hundred or less on the underside of the leaves. 



Life history and habits. The moths appear in June or July 

 and deposit their eggs, and the young upon hatching feed for a time 

 en masse upon the underside of the leaves. This gregarious habit 

 is maintained to a certain extent throughout their larval existence 

 but toward the completion of larval growth they become somewhat 

 separated. As the larvae grow larger they at the same time modify 

 their feeding habits, ultimately devouring the entire leaf structure 

 with the exception of the stem and larger midrib. When not feed- 

 ing, frequently they may be found at rest on the branches or trunk 

 of the host and at that time the rear portion of the body is slightly 

 elevated. 



In September the larvae pass to the surface of the soil, con- 

 struct fragile cocoons among the leaves and trash and there remain 

 until spring. In the spring they transform to pupae and later 

 emerge as moths as indicated previously. 



In Ohio there is one brood per season. 



Nature of work. This is solely a foliage-destroying species, 

 which for the most part confines its activities to the farm and forest 

 rather than to city trees. 



Food plants. The writer has taken the red-humped apple 

 worm as a forest pest on willow and butternut. Other writers have 

 reported it upon aspen and Betula alba. It has been observed or 

 reported upon apple, cherry, plum, pear and other fruit trees. 



Distribution. This insect is generally distributed, having been 

 reported from Canada to the Gulf and from the Atlantic to the 

 Pacific. 



