38 NEW YORK STATE MUSEUM 
eggs near the base 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 partly injured leaves throughout the 
tree or even the entire orchard. 
The feeding on each leaf is, practically speaking, independent 
of that upon other leaves. There is no inclosing and webbing them 
together as with the fall web worm. ‘The small caterpillars feed 
almost entirely upon the upper surface, skeletonizing 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 leaf 
frequently remain untouched, as illustrated in figure 1, a type of 
injury characteristic of moderately infested orchards. Those badly 
infested may have practically every leaf on all the trees completely 
skeletonized, as shown in figure 2. 
Food plants. This insect shows a marked preference for apple 
though it has also been recorded by European writers 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 natural 
enemies, and this is borne out by its classification as a pest of minor 
importance by Continental writers. Doctor Reh gives the following 
list of parasites: Angitia glabricula Holmgr., Meso- 
chorus pectoralis Rag., Microgaster species, Phygadeuon 
and Thryptocera crassicornis Meign. It is possible 
and certainly to be hoped that some of its native enemies have 
become established with their host. If this is not the case the 
chances favor certain of our native parasites becoming accustomed 
to this new food supply and assisting materially in red*~‘ng its 
abundance. One parasite, Dioctes obliteratus Cresson, 
kindly determined by Mr Gahan through the courtesy of Dr L. O. 
Howard, has already been reared from material received from 
Westchester county. 
Control measures. There is no question but what thorough and 
timely spraying with a poison, such as arsenate of lead, will destroy 
the caterpillars and, owing to their feeding almost entirely upon 
the upper surface of the leaves, a general application of these 
measures in infested areas to all trees upon which the pest can 
subsist would mean its early control and practical elimination so 
far as material damage is concerned. Furthermore, the adoption 
of such measures would be a most effective check upon a rapid 
spread and consequent extensive injury. Residents of the infested 
