136 NEW YORK STATE MUSEUM 



September though as a general rule they are scarce. One small tree was 

 observed in 1902 which had suffered severely from a second brood of this 

 insect and a number of nearly full grown caterpillars were present the latter 

 part of August. 



The young larvae feed on the under surface of the foliage [pi. 7, fig. 6], 

 and as they increase in size more and more holes are eaten, till when full 

 grown all hut the main ril>s of the leaves, well representml in plate 7, are 

 devoured. A peculiar habit, recorded by the late Dr Lintner but not 

 observed by others outside of Albany, is the girdling of elm twigs by the 

 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. 7, fig. 8]. 

 The affected tips soon die, break off, and fall in numbers to the ground. 

 The larvae drop from the trees rcadil\-, s[)ccially when young, suspending 

 themselves by silken threads, and then. may be blown or carried consider- 

 able distances. When nearly full grown, the caterpillars travel to a great 

 extent ; this is saiil to l)e specially true of the larger ones, females, and 

 more likely to occur if they are very abundant. At such times there may 

 be quite a migration to other trees. The cocoons are found very generally 

 on the trunks ami particularly on the underside of the larger branches. 



The wingless females, at llie time they emerge from their cocoons, 

 attract large numbers of the opposite sex. Dr Lintner records an instance 

 of one attracting one hundred males within an hour. Collections at electric 

 lights in Poughkeepsie N. Y., by Dr Dyar, show that the males fly during 

 July ami into August. 



Food plants. This insect, though commonly destructive to compara- 

 tively few trees, has been recorded as feeding on a number of others, as the 

 following list will show : linden, horse-chestnut, buckeye, maples (specially 

 the soft and Norway), bo.x elder, honey locust, apricot, garden plum, wild 

 plum, garden cherry, chokecherry, rose, pear, apple, quince, ash, elm 

 (several species), sycamore or buttonwood, butternut, black walnut, hickory, 

 oak, birch, alder, willow, poplar, s]>ruce, fir, larch and cypress. 



Distribution. This native siiccies "ranges from Jacksonville V\a.. to 

 Nova Scotia on the eastern coast and e.xtends west certainlv as far as 



