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NOTES ON THE PACIFIC COAST SPECIES OF ORGYIA, 

 WITH DESCRIPTIONS OF LARV^^ AND NEW FORMS. 



By Henry Edwards. 



Four species of the genus Orgyia, are known by me to exist 

 in California and the adjacent states, two of which appear to be 

 as yet unknown to science, though one of them stands in such 

 puzzHng relationsliip to an aUied form, that it is almost impossi- 

 ble to assign its true position as a species. The remarkable dif- 

 ference in the larval stage (which appears to be constant in both 

 instances), is our only reliable guide as to the specific value of 

 either, and a reference must be made to the early conditions of 

 both insects, by those who wish for a perfect understanding of 

 their relations to each other. The food plant is different in these 

 two forms, and one {O. vdusta) is extremely rare where the 

 other {O. gulosa) is found in abundance, \w\\\\q O. giilosa is not 

 met with at all in the district in which O. vetiista is common. It 

 is possible that both of these forms were known to Boisduval, 

 and it is difficult to state positively which he intended to describe 

 as O. vetrista, but a specimen which I had the opportunity to 

 examine in the collection of Mr. Lorquin, of San Francisco, (by 

 whose father most of the Lepidoptera of California, described by 

 Dr. Boisduval had been collected), was decidedly belonging to 

 the larger and more frequent form, and it is from this standpoint 

 that the present paper is written. 



I append descriptions of the larva as well as of the imago, of 

 both of these closely allied form?. 



Orgyia vetusta. Bois. 



Larva. Full groivn. 



Ground color, velvety black. Head black, rather shining 

 with a yellow line in front ; mouth parts bright yellow. From 

 the second segment spring two bundles of long black hairs, as in 

 all the species of the genus. . The space between these is bright 

 Vermillion red ; at the base of each segment is a series of 4 or 6 

 orange yellow dots, extended also to the sides; 3rd and anterior 

 part of 4th more broadly and distinctly patched with orange. 

 From the dorsum of 5th, 6th, 7th and 8th spring bundles of long 

 silky hairs, whitish drab at their base, chestnut towards their tips. 

 Along the lateral region is a double row of bright red tubercles, 

 and' on the 3rd, 4th, 10th, nth and 12th, these extend across the 

 body, 6 tubercles appearing on each segment. Out of these 

 spring a series of long yellowish white hairs, sparsely interspersed 

 with black, and becoming more decidedly yellow laterally. From 

 the centre of 12th segment, a bundle of long yellow hairs, tufted 

 with black ; under side blackish ; feet and pro-legs orange yellow, 

 with the claws black. 



Lenp;th i.oo inch. 



