570 Agricultural Experiment Station, Ithaca, N. Y. 



What They Are. 



These green fruit worms are large, light yellowish or apple- 

 green caterpillars, with a narrow cream-colored stripe down the 

 middle of the back, a wide cream-colored stripe along each side, 

 and many similarly colored mottlings or spots which sometimes 

 form quite distinct stripes along the body above the broad lat- 

 eral stripes. When fully grown they range from an inch to an 

 inch and a half in length. Some of them are shown at work in 

 the illustration on the title page, and at a, plate 2 ; figures f and (jr, 

 plate 1, c and d, plate 3, and h, plate 2 are from photographs of 

 the worms taken twice natural size. Like many other caterpil- 

 lars, these green fruit worms are the offspring or younger stage 

 of insects known as moths or millers. These adult forms are 

 represented natural size at &, plate 1, at a, plate 3 and at f, plhte 

 2; and also twice natural size in the same plates. 



Habits and Food of the Caterpillars and Moths. 



For several years before the fruit-eating habit of these green 

 fruit worms w^as discovered, they were known to feed upon the 

 leaves of the apple and several forest trees; the leaves of poplar, 

 hickory, wild cherrj^, box-elder, and the buds of roses are recorded 

 among their food-plants. During the summer of 1870, however, 

 the insects attracted unusual attention in Missouri and Illinois by 

 being frequently found eating or boring into apples, peaches and 

 the spongy oak-apple (a large apple-like swelling or gall often 

 produced on oak-leaves by a minute gall-fly). This year, pears, 

 peaches, plums, currants, and quinces were eaten in New York 

 state, but the caterpillars confined themselves mostly to an apple 

 diet. We have not observed the worms boring into the fruit. 

 They simply begin eating on one side and often continue feeding 

 until nearly half of the fruit is eaten, leaving a large cavity on 

 that side (see illustration on title page, and figure a, plate 2). 

 They work during May and the first half of June, and are not to 

 be found on the trees again during the year. The insects go from 

 fruit to fruit, one caterpillar thus ruining several fruits; an 

 instance is recorded of one worm destroying six of the eight 

 quinces on a tree. The caterpillars feed during the day, and 



