INSECT PESTS OF OHIO SHADE AND FOREST TREES 313 



Life history and habits. — The winter, in all likelihood, is passed 

 as pupae within the soil, the adults emerging in late May or early 

 June. Eggs are deposited upon the unfolding leaves and the larvae 

 soon make their appearance. They are found in great quantity 

 upon the underside of the leaves, snug against the midrib and veins, 

 being aided materially in maintaining their position by reason of 

 the short down which clothes this portion of the leaf. As early as 

 June 5 larvae in abundance have been observed at Wooster. Within 

 a short time, some of the larvae change to pupae within their re- 

 treats on the leaf, others transform within the shelter of the mal- 

 formed growing tip of the host, but probably the greater number 

 drop to the ground and perform their transformations beneath the 

 surface of the soil. 



The life cycle is completed during midsummer in from 3 to 4 

 weeks, according to Prof. H. A. Gossard (48). There are several 

 generations annually, but the two broods of larvae appearing in 

 early June and early July, respectively, do the greatest injury. 



Nature of work. — The stunted growing tips of catalpa ; the dis- 

 torted leaves ; the brown eye-like spots or larger browned, deadened 

 areas on the leaves and the distorted, misshapen pods all are the 

 effects of the activities of this insect. 



The injury to the foliage may take the form of circular feeding 

 punctures about one-fourth of an inch in diameter (See Plate LIX, 

 Fig. 4), or in the event of a destructive attack the entire leaf may 

 wilt (See Plate LX, Fig. 1), later becoming brown and crumpled. 

 (See Plate LX, Fig. 2.) Frequently the trees may shed a consider- 

 able part of their foliage as a result of early summer outbreaks. 



When the larvae gain access to the pods considerable distortion 

 results and if abundant, the greater part of the seed may be de- 

 stroyed. (See Plate LIX, Fig. 5.) 



The most serious aspect of the injury by the catalpa midge 

 consists in the stunting and dwarfing of the trees as a result of the 

 constant killing back of the terminal bud. (See Plate LX, Fig. 3.) 

 When grown for posts or poles it is vitally important to rapid and 

 satisfactory development that the terminal shoots and particularly 

 the central one remain healthy and vigorous. Repeated injury to 

 the terminal shoot causes excessive branching and the outcome is a 

 dwarfed bushy growth instead of the straight, upright tree. (See 

 Plate LX, Fig. 4.) 



Food plant. — Catalpa is the only known host. 



Distribution. — The catalpa midge has been reported from the 

 District of Columbia, Indiana and Ohio. Doubtless, however, it is 



