46 THE EEPOET OF THE No. 36 



west in Asia to Turkestan. This range suggests that the species can maintain 

 itself in the northern United States an(d southern Canada. 



It has become established in New York State in an area determined in 

 co-operation with Dr. G. G. Atwood of the State Department of Agriculture as 

 centering approximately upon Irvington and extending east to White Plains, 

 south to Harrison and north to Croton. It also occurs on the west bank of the 

 Hudson Eiver, ranging for a mile or two north and south of Nyack and west 

 to West Nyack. 



Life History. It has not been possible to work out the complete life 

 history of this insect under American conditions though there is no reason for 

 thinking that the moth has departed materially from its habits as recorded in 

 Europe. Mr. J. W. Tutt states that adults occur in September and October on 

 flowers of Compositse, while William West records capturing specimens among 

 golden-rod. 



The adults and probably pupae hibernate, the former in any shelter such as 

 thatch and the latter in cocoons attached to the leaves. The over-wintered moths 

 or those issuing from pupae deposit eggs probably when the leaves are partly 

 developed, since Meyrick records larvfe as occurring in England during May, 

 June and August, indicating at least two and probably three generations annually. 

 There is considerahle variation in development toward the end of the season, at 

 least under American conditions. Full-grown and very small larvae were found 

 simultaneously at Irvington in September and even in early October. A few 

 larvae may feed to the latter part of the month. Larval growth is probably 

 completed within a month or six weeks. The type of injury suggests that the 

 moths deposit a few eggs near the hase of each leaf and when numerous may 

 oviposit on almost every leaf. One of the striking features of an infestation 

 is the general distribution of injury throughout the tree. 



The feeding on each leaf is, practically speaking, independent of that upon 

 other leaves. 'There is no inclosing and webbing together as with'^the fall web- 

 worm. The caterpillars feed upon the upper surface, skeletonizins; the leaves 

 more or less completely and working from the lower part of the midrib upward 

 and outward so that unless the infestation is unusually severe areas on each 

 ;Side of the basal parts of the leaves frequently remain untouched. This type 

 of injury is characteristic of moderately infested orchards. Those badly infested 

 may have practically every leaf on all the trees completely skeletonized. 



Food Plants. This insect has shown a marked preference for apple though 

 it has also been recorded as feeding upon pear, hawthorn, mountain ash, birch 

 and possibly willow. 



Natural Enemies. Meyrick's statement to the effect that this skeletonizer 

 is local in England indicates moderately efficient enemies and this is borne out 

 by its classification as a pest of minor importance by continental writers and 

 the recording by Eeh of a number of parasites. It is presumable that some of 

 its native enemies became established with their host and if this is not the case, 

 the chances favor some of our native parasites becoming accustomed to this new 

 food supply and assisting materially in reducing its abundance. A few parasites 

 (Diocfies obliUratus Cresson) Mndly determined through the courtesy of Dr. 

 Howard, have already been reared from materials received from Westchester 

 County. 



Control Measures. There is no question but that thorougli and timely 

 spraying with a poison such as arsenate of lead will destroy these caterpillars 

 and, owing to their feeding almost entirely upon the supper surface of the leaves. 



