128 PROCEEDINGS OF THE CALIFORNIA 



Pacific Coast Lepidoptera.— No, 19. Notes on a Singular 

 Variety of the Larva of Halesidota Agassizii. Packd. 



BY HENEY EDWARDS. 



It has generally been conceded by entomologists that variation of certain 

 characters in either of the stages of insect life, so long as that variation is 

 contained within what has been called the " well denned limits of a species," 

 does not constitute a ground for founding new species upon trivial differ- 

 ences. But remarkable changes in the larvae of certain forms are decidedly 

 the groundwork upon which other ideas may arise, and are the beacons which 

 light us to a better understanding of the laws which govern the many devel- 

 opments of animal life, which, with their almost countless variations, lead us 

 to the conclusion that our positive knowledge of what really constitutes a 

 species is very limited in extent, and compel us to the confession that we can 

 say but little as to where a species is true to its original type, or how far its 

 wanderings may extend. It is a singular fact that the genus Halesidota 

 should present two kindred instances of the variation of the larval stage to 

 such an extent as almost to warrant the assumption that new species had in 

 these cases begun to assert their existence; but it is nevertheless so, the 

 one to which I am about to refer being even more remarkable than that 

 spoken of by the late Mr. B. D. Walsh, in Proc. Boston Soc. Nat. Hist., 

 Feb., 1864, and further alluded to by him in the Proc. Ent. Soc, Phil., Nov., 

 of the same year. To those who are not familiar with Mr. Walsh's 

 papers, it may be briefly stated that he found feeding upon oak some larvae 

 of this genus, differing very much, both in color and in the arrangement of 

 the pencils of hairs, from those of the well known Atlantic species, H. tesse- 

 laris, but which, upon arriving at their perfect state, could not possiby be 

 distinguished from the irnagos of that species. Mr. Walsh, regarding the 

 larval condition as of equal value with the subsequently matured form, called 

 his new discovery by the name of If. Antiphola, and always referred to it as 

 a phytophagic species, and not a phytophagic variety. Mr. Grote, on the 

 other hand, in Proc. Ent. Soc, Phil., December, 1864, alludes somewhat 

 slightingly to Mr. Walsh's experiments, and considers the Antiphola of the 

 latter author as merely an accidental variety of the better known and more 

 abundant form; and this, it is but fair to say, is the conclusion arrived at by 

 most other entomologists. It gives me great pleasure to be able to add some 

 few facts bearing upon this interesting question, and to present the descrip- 

 tion of some larvae, which, at the time of their capture, certainly appeared 

 to me to be those of a totally newandundesciibed species, but which, in their 

 imago condition, can ii>no possible character be distinguished from the well 

 known California species, H. Agassizii of Packard, =Phcegoptera solids, Bois. 

 My specimens were taken by myself in August, 1865, in Strawberry Valley, 

 near Mount Shasta, one of them feeding upon alder (Alnus viridis), and the 

 other upon a species of willow. For the better comparison of the singular 



