CECIDOMYIA. 197 



aided in this by a resinous substance which they exuded abund- 

 antly. Having reached a certain height on the leaf, they stop and 

 remain quiet till the resinous substance covering them becomes 

 hard and assumes the shape of an oblong, whitish, semi-transparent 

 cocoon. Then the larva may be seen moving to and fro inside of 

 this cocoon. I did not succeed to rear the fly from the cocoons 

 which I brought home, and when I returned to the same spot in 

 the woods about a month later, the cocoons were already empty. 



According to Ratzeburg's statement the European species spends 

 the winter in the cocoon. The American species, as just shown, 

 forms its cocoon only in the spring. As, nevertheless, it may be 

 identical, or at least closely allied to G. pini Degeer, I subjoin here 

 the description of the latter, translated from Mr. Winnertz's mo- 

 nograph. (Compare also Ratzeb. 1. c. Ill, p. 159.) 



C. (Diplosis) pini Degeer. J* Antennas somewhat longer than 

 the body, brown, basal joints yellow, verticils snow-white ; joints 

 strong, stout, on short pedicels, double joints three times as long 

 as the pedicel, the last joint with a very small, nipple-shaped pro- 

 jection ; hypostoma and front pale reddish or brown ; palpi reddish- 

 yellow; thorax brownish-black or black, with two rows of white 

 hairs from the collare to the scutellum, and one row from the shoul- 

 der to the origin of the wing ; pectus blackish ; pleurae reddish- 

 brown ; halteres white ; abdomen reddish-brown, with white hair, 

 forceps blackish ; feet brown with white articulations, under side 

 silvery-white ; posterior feet with a silvery-white reflection when 

 viewed in a certain light ; wings milky white, with a white pubes- 

 cence, the costal and the two first longitudinal veins brown, the 

 third longitudinal vein pale; transverse vein pale, but distinct, 

 very oblique, situated a very short distance beyond the middle of 

 the first longitudinal vein ; third longitudinal vein straight, turning 

 towards the posterior margin in an obtuse, rounded angle ; the 

 second longitudinal meets the costal immediately beyond the tip of 

 the wing. 



9 Antennas a little more than half as long as the body, brown 

 with gray verticils, basal joints yellow; joints of the flagellum 

 about five times as long as the pedicel, last joint ending in a small 

 bud-shaped appendage ; hypostoma reddish-yellow ; front reddish- 

 brown ; palpi and thorax as in J 1 ; halteres brown ; abdomen red- 

 dish-brown, with short whitish hairs, more dense and with a silvery 

 reflection laterally ; ovipositor short, yellow, with two small oval 



