328 



PSYCHE. 



fjanuary i8 



THE ARCTIC LYMANTRIID LARVA FROM jNIT. WASHINGTON, 

 N. H. {DASrCHIRA ROSSI! CURT.?) 



BY HAKRISclM G. DYAR, NEW YOIIK, N. Y. 



About twenty years ago, Mr. Grole 

 recorded (Psyche, I, 131) the capture 

 on Mt. VVasliington, aljove timber line, 

 of an Arctic form of Lymantriidae which 

 he referred to as a variety of Laria ros- 

 .s// Curtis. Last summer a number ot 

 larvae occurred to me on Vaccininm and 

 Betula near the summit which I believe 

 to be the larvae of tills species. Others 

 were found by Mrs. A. T. Slosson and, 

 near the top of Mt. Adams, by Master 

 Richard Seager. The larvae do not 

 agree with Dr. Packard's description of 

 Laria rossii (Amer. Nat. xi, 52) taken 

 by the Polaris expedition in northfrn 

 Greenland, but neither tlid his moths 

 quite correspond, and he may have had 

 before him examples of Dasvchira 

 S^roetilandica in which the hind wings 

 are colored as he describes. The original 

 locality for rossii. in Boothia is much 

 nearer to our own region than is north- 

 ern Greenland, and true rossii has been 

 recorded from Labrador by Christoph 

 and Moschler ; hence it seems probable 

 that the Mt. Washington race sliould 

 prove more like these. The moths are 

 actually so, showing the yellowish color 

 on the hind wings. 



There seems little doubt but that 

 these Arctic forms are branches of a 

 race represented in Europe by Dasy- 

 chira selcnitica. If we lemove from 

 the larva of selcnitica tlie slender ban- 



pencils which arise from joints 2 and 

 12, we should have a very close ap- 

 proximation to the larva described by 

 Dr. Packard ; and if we further modifx' 

 the same larva by adding tufts on joints 

 10 and [I, like those already present on 

 joints 5 to 9 and 12, we should have 

 practically tlie Mt. Washington larva. 



Curtis describes the larva of D. rossii 

 as follows: "Large and hairy, of a 

 beautiful shining velvety black, the 

 hairs being somewhat ocherous ; there 

 are two tufts of black on the back, fol- 

 lowed by two of orange." Unfortu- 

 nately this meagre statement leaves the 

 question open as to whether D. rossii 

 is like Dr. Packard's larva or mine. 

 Perhaps the '' two black and two orange 

 tufts " refers to the younger stages ; it 

 cannot refer to either Dr. Packard's 

 mature larva or to mine. In the rest 

 of the description there is no mention 

 of the absence of tufts from joints 10 

 and II, and the presumption would be 

 that the larvae were uniformly tufted 

 like my Mt. Washington ones. How- 

 ever, I recognize that too much weight 

 should not be given to omissions in 

 such imperfect descriptions. 



The following is a description of the Mt. 

 Washington larv.Te : Head rounded, velvety 

 brown-black, densely hairy; clypeus black, 

 smooth ; a reddish shade on the posterior 

 side of head ; widtli 3.2 mm. Warts normal 



