OF NORTH AMERICA. 121 



A variety of the 5 occurs in which all the parts which are yellow 

 in the type, have a pale whitish tinge. It appears to be confined to 

 specimens in which the dark colors preponderate as in fig. 13. 



Expanse 0/ ivings, $, i.i5toi.30, ? 1.30 to 1.45 inches. Letigth 

 of body, 0.45 to 0.55 inch. 



Habitat. — California, (Edwards, Stretch, Behr, Behrens.) Nevada 

 (Edwards), Oregon (Lord Walsingham). 



A widely distributed insect, not uncommon where it is found, but 

 somewhat local. It flies during the hot sunshine, in wooded districts 

 in May. Boisduval's Lithosia Una and L. adnata are founded on va- 

 rieties of this species. The former name is retained as having a wider 

 range. I strongly suspect that Pltaarctia inodesta, Packard, is one of 

 the many varieties of this species, although a specimen forwarded to 

 Dr. Packard was returned with the query, "what is it.-*" That it is 

 congeneric is, I think, beyond doubt, as the peculiar thoracic markings 

 are minutely given in the diagnosis of P. modesta. 



The wonderful variations of this species, show how necessary it is 

 to have a long series of many insects before it is possible to determine 

 the limits of the species. It is possible to select three or four types of 

 the insect under consideration, so unlike each other, that in the ab- 

 sence of the intermediate gradations they might readily be considered 

 specifically distinct ; it was indeed a long time before I could satisfy 

 myself of their identity, especially as the shape of the primaries is b)' 

 no means constant, but the past summer has supplied so many inter- 

 mediate links that there can no longer be any reasonable doubt. 



2.-LEPTARCT1A DECIA. (PI. 5, figs. 1, 2, 15.) 



Lithoiia decia, Boisduval, Ann. Soc. Ent. Belg. vol. 12, p. 72 

 (1868-9). 



6 . — Head and its appendages brownish black. Patagia, thorax 

 and abdomen brownish black, the latter with a reddish lateral stripe. 

 There is a narrow whitish line on the outside of the prothorax, a nar- 

 row whitish line on the patagia, and a few whitish scales on the vertex, 

 sometimes more or less obsolete. Legs dusky, inside of femora pink- 

 ish, inside of tibiae and tarsi yellowish. 



Anterior wings reddish brown, sprinkled with grey scales, and 

 crossed by three obscure, irregular darker lines, one subbasal, one 

 median and the third submaririnal. There is also a distinct whitish 



