110 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Kilcy tlius describes (in our Report on Foi'ot Tree Insects, p. V2~)) tiie fully fed lurva 

 recei\ed by liini from Cedar County, Iowa: 



'^ Ldi'i'ii. — Head large, fully as wide as the body: jet bhuk. Body uniforudy thick, cylin- 

 drical. On inesothoracic seg-nient a pair of long- and slender, stitl', black spines, blunt at the end, 

 nearly as long as the body is thick. They stand erect, diverging a little, and arise from swollen 

 bases, connected by a slight transverse ridge. On each succeeding segment there is a transverse 

 series of four small, shary), simple spines, one or two sometimes ending in two spines; and low 

 down on each side, l)el()w the spiracles, are three large and a fourth minute short acute spine. 



"There are on the hinder part of the back of most of the segments two small black spines. 

 The spines become larger on the last three, especially the penultimate segment. Supraanal plate 

 large and flat, rather rough, ending in two acute spines, with four smaller spines on each side. 

 Abdominal legs larger and broad, with stiti' short hairs on the hinder and lower edge. 



'■Rrothorax unarmed, but with a thickened conical plate. Body jet-))lack, with a double 

 dorsal ocher-yellow-brown line, a narrow subdorsal line, and two wavy lateral lines of the same 

 color. A median ventral ocher-brown band. Length, 42 mm." 



Food plant H. — Oak of diflcrent s]>ecies and, rarely, the birch and raspberry. 



Hahits. — The prickly caterpillars of this species, during certain years, as I have noticed at 

 Amherst, Mass., and at Providence, as well as in Maine, so abound as to nearly strip large oak 

 branches of their leaves, and it is perhaps the most destructive of all our caterpillars to the 

 foliage of the oak. The spines, if they happen to penetrate the skin, as Fitch and others have 

 observed, sting like nettles. This species, Mr. Riley informs me, is the more, injurious in the 

 Northern States, while A. xfifjnia is most destructive in the Southern. According to Riley, 

 Mr. Bassett has bred a small ichneumon fly {Lirinieria (BanchiiK) fugJfiva Say) from this cater- 

 pillar. Riley has alsy bred it from the larva of Anhofn stigma ^ ClixiocoiiijKi xi/lrattra. as well as 

 other caterpillars. 



Mr. Lintner states that "the larva- occur so abundantly at Center as wholly to defoliate 

 immbers of the smaller oaks. On the 7th of July the female moths were seen to have connnenced 

 the deposition of their eggs on the under side of oak leaves in patches often nearly covering the 

 entire surface. On the 11th of July some newly hatched larva^ were observed." (Ent. Contr., 

 I, p. 58, footnote 1.) 



In lS8i this caterpillar was very destructive to oak forests in Pennsylvaruu. Professor 

 Claypole writes to the Canadian Entomologist (X^', p. 38): 



"I have seen hillsides that looked as if tire had passed over them in consequence of the 

 desti'uction of the foliage by millions of this species. In the woods they could be found crawling 

 over almost every square foot of ground and l.ving dead by dozens in every pool of water. The 

 sound of their falling '" frass," too, was like a slight shower of rain. Farmers tell me they have 

 never known them so abundant before within their recollection. Harris says this species lives 

 on the white and red oaks in Massachusetts. Here the white oaks were untouched and the red 

 oak is not abvmdant. The food of the caterpillars was almost exclusively the foliage of the l)lack 

 oak ((^JiifiTus t/ncton'it), the scarlet oak (('^A cocr/'nea). and the bear or scrub oak (tj. iHcifotio). 

 (See also American Naturalist, X\'l, p. itl-1.)" 



It was also abundant in September of Ihe same year in Sagadahoc and Cuml)erland counties. 

 Me., and in Rhode Island. 



In the season of l8S>i K. C'larkson observed the destruction to oaks in Columbia County, 

 N. Y. "The moths," he says, "pair in the grass under the oaks, very shortly after pupation, 

 and as the wings of the female are small in proportion to the size of her Ixxly, she is unable to 

 make a very extended flight. The eggs, as discovered In* me, were attached to the under side 

 of the leaves at the terminal twigs of all the l)i'un<'hcs nearest the ground, the branches at an 

 elevation of 12 or 15 feet not showing a single deposit." (Papilio, II, p. 189.) 



In Minnesota the caterpillar is regarded as the most common and injurious insect to oaks 

 in the State, white, scarlet, and scrub oaks being stripped of their foliage. "I have seen," 

 says Lugger, "such caterpillars so numerous that the whole ground in the forests was covered 



