446 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



aud during the last week of April and the first of May the moths are 

 to be found in great numbers." On the 6th of May the moths laid glob- 

 ular eggs .04 inch in diameter, depositing them some days before the 

 leaves expand. May 29 the larvte began to hatch out just as the pop 

 lars were throwing out their leaves. The larvae change but little during 

 growth. At the end of July they descend and bury themselves in the 

 enrth, changing in a few days to pupie, without forming any cocoon. 



The larva is from 2 to 2^ inches loijg, of a drab or diugy purple ; head of a lighter 

 shade aud spotted with black. First segment behind the head bordered in front with 

 a yellow line, indented beliiud ; fourth to eighth inclusive, each with six very small 

 yellow tubercles, two on the back, one behind, and one below each spiracle. Body 

 striped from head to tail with twelve reddish lines, each bordered on both sides by an 

 irregular narrow black line; six of the reddish lines are on the back and sides, one 

 ( interrupted) through the spiracles, and four on the abdomen. Anal segments spotted 

 with black, as also first, second, and third segments. Mouth pinkish, legs pink, 

 spotted with black ; spiracles dark. (Bowles.) 



The moth. — This genus may be known by the large heavy body and rather small 

 wings; the fore-wings have the costa straight, the tip subrectangular ; the male 

 antenna} with long pectinations. This species is dark granite-gray, the fore-wings 

 with three transverse, obscure, dusky lines, represented in rubbed specimens by 

 black spots on the costa and veins. First line well curved ; second aud third lines 

 near together. Half-way between the third line and the outer edge of the wing is a 

 fainter band than the others, represented by a costal square spot, and ablack spot on 

 the inner angle. Hind wiugs with three transverse diffuse bands. The fore-wings 

 expand 1.55 to 2 inches. 



12. The tussock catehpillar. 

 Orgyia leucostigma (Abbot and Smith). 



The injury done to the silver-leaf poplar in New York City by this 

 caterpillar has been marked ; it was especially noticeable in 1883. Mr. 

 F. Clarkson states that many of the trees in that city were entirely 

 denuded of their foliage, particularly the silver-leaf poplar, the ailan- 

 thus alone escaping attack. He suggested to the authorities the pre- 

 vious spring that hand-picking of such cocoons as bore the eggs was 

 the only sure way of exterminating these insects. There is good reason 

 to believe, however, that what the authorities have failed to do a 

 young army of parasites (Pimpla), which have put in an appearance 

 during the last fortnight, are now actively attempting, and we shall 

 probably be rid of this moth another year. The ova commenced to 

 hatch out about the 25th of May, and the larvjie began to assume the 

 pupa form about the 21st of June ; ten days thereafter the imago was 

 discovered depositing ova." Out of twelve cocoons four yielded the 

 ichneumons. Mr. Clarkson noticed that this parasite forced its eggs 

 through the cocoon on the pupa and that in every case he observed 

 the pupa selected was a female, doubtless from the fact that "its plump 

 condition provides the necessary food for the development of the para- 

 site, which the male pupa of the moth could not furnish." (Can. Ent., 

 XV, p. 168.) 



