BIRCH CATERPILLARS. 489 



1869, V. 1, p. 48) calls attentiou to the squeaking noise produced by the larva of this 

 and of other species of (SnimntAMS. Lintner (Entoui. Contrib. [No. 1], 1869, p. 56) 

 gives Pruniis pennsylvanica and Cratwgus as food plants of the larva. Mann (Psyche, 

 September and October 1877 [8 Mar. 1878], v. 2, pp. 69-72) compares descriptions of 

 the larva of this and of other species of Smerinthus, giving Acer as food-plant of the 

 larva of S. excacatus. Goodell (Psyche, July [Dec] 1882, v. 3, p. 368) describes egg 

 and first larval stage of this species. Fletcher (Can. Entoni., Nov. 1883, v. 15, pp. 

 203-204) gives as food-plants apple, plum, wild cherry, Populus balsamifera and P. alba, 

 and further stales that the larvte varied much in coloration. Saunders (Can. Entom., 

 Jan. 1834, v. 16, pp. 9-11) describes and figures the last stage of the larva and the 

 imago. Fischer (oj). cit., p. 17) adds Tilia and Salix to the food-plants. lu Cam- 

 bridge, Mass., the larva of this species is not rare ou low shrubs of Betula alba, where 

 it occurs throughout August and September. The larvte, as observed on Betula nlba, 

 exhibit no variation. They are somewhat difficult to rear; of thirty-eight larvae, of 

 which rearing was begun, eight were put in alcohol for preservation ; three produced 

 images (2 males and 1 female) ; sixteen died without apparent parasitism, while eleven 

 were killed by Thyreodon morio, of which ichneumon only two reached the imago state. 

 One of the pupfe of Thyreodon produced a large number of minute hymenoptera — sec- 

 ondary parasites. The egg of S. excwcatus often harbors very minute hymenopterous 

 parasites ; more than thirty of these hymenoptera sometimes emerge from a single egg 

 of Smerinthus, a fact that will give an idea of their microscopical minuteness. 



14. The Hickory Tussock-worm. 



Halesidota caryce (Harris). 



1 found August 28, at Brunswick, Me., a whole brood of these cater- 

 pillars on a birch tree, almost covering both the upper and lower sides 

 of a leaf. 



15. The Wooly Bear. 



Spilosoma virginica (Fabr.). 



The " wooly bear " caterpillar of this species is a general feeder, and 

 is said, among other trees which Mrs. Dimmock enumerates below, to 

 feed on the white birch. 



She also adds to the list of birch-feeding insects Pyrrharctia Isabella* 

 (under the name ^^ Spilosoma isahelW), though as it apparently has 

 only fed on this tree while in confinement, we should as yet scarcely 

 regard it as aflfecting this tree. 



Spilosoma virginica Fabr. (Syst. Entom., Suppl., 1775, p. 437). Harris (Rept. Ins. 

 injur. Veg., 1841, p. 247, 248) describes the larva and imago, stating that the larva 

 feeds on leaves of Plantago, Pisum, Phaseolus, Zea mays, Graminece, Vitis, Bibes rubrum 

 and B. grossitlarla ; later (Treatise ou Ins. injur. Veg., 1862, p. 349-351) he adds a 



* Spilosoma Isabella Abb.-Smith (Nat. Hist. Lepid. Ins. Ga., 1797, v. 2, p. 131, pi. 66). 

 Harris (Rept. Ins. injur. Veg., 1841, p. 252, 253) describes larva and imago giving 

 Trifolium, Taraxacum dens-leonis, and. narrow -lea ved P/a« /a^fo as food-plants; to this 

 he adds (Treatise on Ins. Injur. Veg., 1862, p. 3,55, 356) a figure of the larva. Walsh [?} 

 (Pract. Entom., June, 1867, v. 2, p. 103) gives apple as a food-plant of the larva. 

 Riley (Amer. Entom.. April, 1870, v. 2, p. 182) figures and briefly describes the larva, 

 pupa, and imago, mentioning only grass as a food-plant of the larva ; later (4th Ann. 

 Rept. State Entom. Mo., 1872, p. 143, 144) he reprints these figures. Riley's figures, 

 with a brief description, are again repeated by Saunders (Cau. Entom., April, 1873, 

 V. 5, p. 75-77, and Ann. Rept. Entom. Soc. Ontario, 1873, p. 22, 23), and Westcott 



