BIRCH CATERPILLARS. 489 
1869, v. 1, p. 48) calls attention to the squeaking noise produced by the larva of this 
and of other species of Smerinthus. Lintner (Entom. Contrib. [No. 1], 1869, p. 56) 
gives Primus pennsylvanica and Crataegus as food plants of the larva. Mann (Psyche, 
September and October 18/7 [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. exccecatus. Goodell (Psyche, July [Dec] 1882, v. 3, p. 368) describes egg 
and first larval stage of this species. Fletcher (Can. Entom., Nov. 1883, v. 15, pp. 
203-204) gives as food-plants apple, plum, wild cherry, Populm balsamifera and P. alba, 
and further states that the larvje varied much in coloration. Saunders (Can. Entom., 
Jan. 1884, v. 16, pp. 9-11) describes and figures the last stage of the larva and the 
imago. Fischer {op. cit., p. 17) adds Tilia and Salix to the food-plants. In Cam- 
bridge, Mass., the larva of this species is not rare on low shrubs of Betula alba, where 
it occurs throughout August and September. The larvae, as observed ou Betula alba, 
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 
imagos (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 pupae of Thyreodon produced a large number of minute hymenoptera — sec- 
ondary parasites. The egg of S. excoecatus 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 Isabella"), though as it apparently has 
only fed on this tree while in confinement, we should as yet scarcely 
regard it as affecting this tree. 
Spilosoma virginica Fabr. (Sysc. Entom., Suppl., 1775, p. 437). Harris (Kept. 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, Graminew, Vitis, Bibes rubrum 
and B. grossularia ; later (Treatise on 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 -leaved Plantago as food-plants; to this 
he adds (Treatise on Ins. Injur. Veg., 1862, p. 355, 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 (4fch 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 (Can. Entom., April, 1873, 
v. 5, p. 75-77, and Ann. Rept. Entom. Soc. Ontario, 1873, p. 22, 23), and Westcott 
