8 NEW YORK STATE MUSEUM 



the latter part of June or early in July. There is some deviation 

 from this, as a few individuals spin up early and some caterpillars 

 linger till numerous egg clusters indicate that most of the insects 

 have completed the round of life. The pupal stage occupies from 

 lo to 15 days. The wingless female appears at the end of this period, 

 crawls on her cocoon and shortly deposits eggs as described. There 

 is normally but one annual generation in Albany and. other inland 

 cities, while in New York city and vicinity and in Boston, Mass. 

 there are two broods and at Washington, D. C. there are three 

 generations each year as stated by Dr Howard. 



A peculiar habit, first recorded by the late Dr Lintner and subse- 

 quently observed by us, is the girdling of the elm twigs by larvae of 

 this insect. This is caused by their eating a portion of the bark 

 around the twig near the beginning of the season's growth [pi. i, 

 fig. 8]. The affected ti])s soon die, break off and fall in numbers to 

 the ground. The young caterpillars drop from the tree readily, sus- 

 pend themselves by silken threads and then may be blown or carried 

 considerable distances. The full grown caterpillars desert the trees 

 and wander considerably. This is particularly true of the larger 

 ones which almost invariably produce female moths. The cocoons 

 are spun very generally on the trunks or on the underside of the 

 larger branches. 



Food plants. This leaf feeder exhibits a marked preference in 

 cities for the linden and horse-chestnut, while it feeds readily on 

 elms and maples. It has also been recorded on a number of other 

 trees. 



Natural enemies. This species has a number of natural enemies. 

 Its comparative rarity in the country shows that our native birds 

 must be very efficient natural checks upon this insect. Mr E. H. 

 Forbush states that 47 species of native birds feed on hairy cater- 

 pillars, most of which would probably take this leaf feeder. The 

 robin, Baltimore oriole and cuckoo are among the more valuable in 

 this respect. 



Parasitic insects are also very efficient checks. I'his species is 

 subject to attack by some 21 primary parasites and these in turn 

 may become the prey of 14 hyperparasites. 



Remedies. A simple and very satisfactory method of controlling 

 this insect is the gathering and destroying of egg masses. Several 

 cities and villages in New York State have employed children in this 



