The Fruit-tree Leaf-roller 285 



appearance. In general, we find the body light green in color, the head 

 black, and the thoracic shield dark-colored, at least up to the last 

 molt. The thoracic shield varies, for in some individuals it is light brown 

 on top and marked along each edge. Dyar, in descriptions of these larvas 

 collected in Colorado, calls attention to the great variation and describes 

 in detail several varying individuals. He also describes one lot of larvae 

 as C. vtvidana, but states that it is not more than a variety of argyrospila. 

 In otu- cages in the insectary, the shortest period in which the larvae 

 matured was 22 days; some took considerably longer to mature. Gillette, 

 in Colorado, placed egg masses in sacks tied over the limbs of plum trees 

 and found that the shortest time for a larva to mature was 30 days. It 

 is possible that a scarcity of food prolonged the time in this case. On the 

 other hand, if the food is allowed to become scarce when the larvae are nearly 

 mature it will hasten pupation, and perhaps this was the case in our cages, 

 although Stedman says that in Missouri they mature in 18 to 20 days. 

 Sanderson and Jackson found that the larvae of A. rosaceana matured in 

 22 to 46 days. No doubt there is an equal amount of variation among 

 the larvae of argyrospila. 



The pupa. — When the larva becomes full-grown it spins a very thin, 

 flimsy web in a rolled leaf, or between the leaves that are tied together, 

 and changes to a pupa. The pupa is light brown, and usually a little 

 over half an inch long. It is a very active pupa, wrigghng vigorously 

 when handled. There are two transverse rows of backward projecting 

 hooks on the top side of most of the abdominal segments. The last 

 segment of the abdomen is considerably longer than the others, is tapering, 

 and ends in about six strong chitinous hooks (Fig. 62). 



In the cages in the insectary the pupal stage lasted nine to twelve days, 

 Gillette found that in Colorado the pupal stage averaged, out of doors, 

 about eleven days. 



The moth. — In general the moth is rusty red with two bright silvery 

 spots along the costal margins of the front wings (Fig. 59). The moths 

 vary from three quarters of an inch to an inch in expanse of wings. The 

 males are usually smaller than the females. There is a marked variation 

 in the coloring and markings of the moths; some are much darker than 

 others, and in some the markings are very distinct while in others they are 

 not. 



Our records during the season of 191 1 show that the moths were emerging 

 nearly every day from June 5 to June 2 1 , with the latest moth appearing 

 June 24. Mr. Braucher, who was in the field working on the codling 

 moth, reports that on June 13 the moths were out in very great numbers. 

 It is evident that by the middle of June the moths were emerging in greatest 

 numbers and that they were almost entirely out before July. 



