1892.] NATURAL SCIENCES OF PHILADELPHIA. 159 



GEOMETRID^. 



Glaucopteryx polata Hubn. 

 Glaucopteryx Sabinii Curt, 

 Glaucopteryx immaculata n. sj). 



Expands 22 mm. Uppersitle : Superiors shining silky gray; 

 immaculate. Inferiors immaculate and several shades lighter in 

 color than the superiors. Underside of all wings of a uniform 

 gray of about the same shade as the upperside of inferiors. Anten- 

 nae pectinated. The remaining portion of the insect is black or 

 very dark gray. Mr. IM'Lachlan refers to this as a form of G. Sabinii, 

 but even if it proves to be such, it deserves a name as all varieties 

 do when one cannot say at once, on inspection, what the species is. 

 The most noticeable fact about the Greenland Lepidoptera is their 

 great variability, which is probably owing to the short season in 

 which they live, and perhaps also to their uncertain appearance, 

 due, perhaps, to sudden changes of temperature while they are in 

 the larval or chrysalis condition. 



