182 ENTOMOLOGICAL NEWS IJuilC, '22 



The mine is started from the egg pocket and later extended 

 in a somewhat irregular and linear manner. By the middle of 

 July most of the larvae are nearly three-quarters grown and 

 by the last of July many are full grown and the mines are com- 

 pleted. On the upper leaf surface the mines appear as dry, 

 brown, irregularly linear areas. A few are blotch-like. The 

 number of mines in a leaf varies from one to three, but is 

 usually only one. 



When the greenish larva is full grown it hollows out a cir- 

 cular cavity at the end of the mine. Such cavities are about 

 five or six millimeters in diameter. In this place it constructs 

 a circular, somewhat flat, thin, tough, parchment-like cocoon 

 about four millimeters in diameter. These cocoons push out 

 the upper and lo\ver leaf tissues somewhat into comparatively 

 large blister-like swellings. By the first week cf August all 

 of the larvae are in these cocoons. At this time the tissue over 

 the linear mines starts to break up and this, together with the 

 feeding which took place earlier in the season, cause the leaves 

 to turn entirely brown and start to curl up toward the midrib. 



After the larva enters its cocoon it shrinks longitudinally 

 into a semiquiescent, compact, prepupal stage, in which it re- 

 mains until the following spring, when it transforms to a pupa. 

 The prepupal stage is long and lasts almost from the first of 

 August until the following May. By the first week in Sep- 

 tember the cocoon with the dried leaf tissue over it somewhat 

 resembles a Dcsmodhun seed in color and shape. Later the 

 leaves containing the cocoons and in fact all of the leaves fall 

 to the ground and here the prepupa passes the winter. 



Egg. Width, 0.5 mm. Subcircular, flat, sides slightly convex ; 

 chorion apparently smooth ; transparent when first laid, later becoming 

 translucent and whitish. The egg resembles a flattened globule of 

 water, but of thicker consistency. 



Larva. Length 6 to 7 mm. Width across middle of body about 

 1.7 mm. Flattened, spindle-shaped, tapering both ways from about 

 the middle, more acutely posteriorly; each segment slightly convex 

 dorsally and ventrally ; body deeply notched, composed of thirteen 

 well-defined segments; legs absent; ocelli absent; color light green, 

 contents of alimentary canal sometimes showing as median dark green 

 line ; first segment narrower than second ; first segment with well- 

 defined, large, subquadrate plate on dorsal and ventral surfaces, dorsal 



