BIRCH CATERPILLARS. 491 



states to live on Juglans ; later (Entom. Corresp., 1869, p. 300, pi. 3, fig. 8) lie figures 

 the larva, and adds apple to the food-plants. Walsh (Proc. Bost. Soc. Nat. Hist., 

 February, 1864, v. 9, p. 298,299) first describes the imago and says, "The larva fed 

 on hickory leaves, but I have met with two specimens on the button-wood or syca- 

 more." Packard (Guide, Study Ins., 1869, p. 290, and Bull. 7, U. S. Entom. Comra., 

 1881, p. 77) briefly describes the larva, cocoon, and imago, figuring the last. A single 

 larva of this si)ecies, taken on Befula alha at Belmont, Mass., 12th August, 1882, pu- 

 pated 17th September, and emerged 1st July, 1883. The excrement of the larva has 

 a peculiar form, being cup-shaped, with a deep concavity and comparatively thin 

 walls, which are somewhat shriveled about the margin in drying. The larva, when 

 disturbed, exhales an odor difiicult to describe.. A short time before pupation it turns 

 whitish. (Psyche, iv, p. 297.) 



18. The American Silk-worm. 



Telea polyphemus (Linn). 



I have found this caterpillar in different stages of growth at Bruns- 

 wick, Me., through August, on Betula populifolia. 



19. The Unicorn Caterpillar. 

 Schizura unicornis (Abbot and Smith). 



This caterpillar, which is common in orchards, has been detected on 

 the birch by Mrs. Dimmock, whose notes on it are subjoined : 



Coelodasys laiicornis Abb. and Smith (Nat. Hist. Lepid. Ins. Ga., 1797, v. 2, p. 165, pi. 

 86). Harris (Rept, Ins. Injur. Veg., 1841, p. 306,307) describes the larva of this spe- 

 cies and gives as food-plants plum and apple, and adds to them, on authority of Ab- 

 bot, Prinos vertwillatus. Harris (Entom. Corresp., 1869, pi. 2, fig. 8) gives a colored 

 figure of the larva. Payne (Amer. Entom., October, 1870, v. 2, p. 341) notes that the 

 larva mimics partly dead and partly living margins of leaves. Lintner (Entom. 

 Contrib., No. 3, 1874, p. 131) describes and figures the larva, adding Corylus americana 

 and Prunus virginiaua to the previously known food-plants ; his figure is copied in 

 Amer. Nat., November, 1874, v. 8, p. 691, 692. Packard (Bull. 7, U. S. Entom. Comm., 

 1881, p. 136) adds Cratcegua to the food-plants. The larva also feeds on Betula alha. 



20. Schizura ipomece Doubleday. 



According to Mr. Koebele the caterpillar occasionally feeds on the 

 birch. 



21. Schizura sp. 



Another unicorn-like larva occurred on Betula jjopulifern, Brunswick, 

 August 29. 



Larva. — Head very large, much larger (about twice) than in S. unicornis on elm; 

 full, much enlarged towards the vertex, which is bilobed; a double row of light, 

 almost white, spots down the front, clypens white; side of head whitish brown, and 

 the head elsewhere is marbled with whitish in a net-work of light brown lines. 

 Hump (dorsal) on the first abdominal segment bilobed aud much larger than in uni- 

 cornis ; the two forks of the hump deep reddish. The median brown dorsal line is 

 much broader than in unicornis. Side of thoracic segments not so light green as in 



