84: VARIETIES of 



ment sufficient modification to stamp it as a very distinct race, and to 

 give it very marked characters of its own. It varies almost as much 

 as muralis in its coast localities, but the green forms are exceedingly 

 rare at Cambridge, thus presenting a marked contrast to muralis in its 

 usual localities, where the green is the prevalent form. Occasionally, 

 distinctly green specimens are found, closely resembling the type of 

 muralis, and a form closely allied to, and in fact almost identical with 

 var. par is also found. But a most striking form of impar which I 

 have not noticed in any coast specimens, is a form with the markings 

 and ground colour essentially black and white, the former being, in 

 fact, almost blue-black, and thus forming a parallel variety to Bryo- 

 phila perla var. suffusa. I would particularly keep the name impar 

 for this form, the y of Mr. Farren (vide below), which appears to be 

 peculiar to Cambridge, and, so far as we at present know, does not 

 occur elsewhere. 



Mr. Warren who first described this species, did so under the 

 name of par, assuming incorrectly that Hiibner's par was a species 

 distinct from muralis. His original notes on and description of impar, 

 (under the name of par) are as follows : " More than twenty years 

 ago, I took a pair of a Bryophila at Cambridge, which at the time 

 seemed to me to present decided points of difference from glandifera, 

 but both Mr. F. Bond and the late G. E. Crotch, who saw them, re- 

 ferred them to that species as a variety, and I submitted to their 

 decision. I have taken one or two at intervals since ; but last year, 

 having captured ten, quite fresh, and observing new points of differ- 

 ence, I sent a pair to Mr. Barrett, who forwarded them to Professor 

 Zeller. The latter, at first, returned them as glandifera var. par, but 

 has since, Mr. Barrett informs me, agreed with him that they constitute 

 a distinct species. I will, therefore, now proceed to give, as far as 

 mere description can do it, the main points by which I think the two 

 species may be differentiated. 



1st. The lines and markings of B. glandifera are much more 

 sharply and distinctly marked than in B. par, which has, so to speak, 

 a more mealy look. 



2nd. Though the lines and markings of the two insects are 

 exactly alike, B. par has all the lines starting as dark spots 011 the 

 costa, and a decided dark line at the base of the cilia of both wings, 

 but especially the hinder ones. 



3rd. B. glandifera etains its green tinge after death, which con- 

 tinues for years if exchv ed from light. B. par, .which, when fresh 

 and alive, is of a much paler green, often with a beautiful pink tinge, 

 fades directly it is killed, or when worn, to a dirty brick colour. 



4th. While B. par has only, so far as I know, been taken in this 

 country, on old walls at Cambridge, B. glandifera is, I believe, a coast 

 species. 



Lastly. B. glandifera runs slightly larger than the nearly allied 

 species. I may add that a form of B. glandifera occurs, which has the 

 mealy appearance of B. par, but without the dark costal markings and 

 dark line at the base of the cilia, which are always observable in the 

 latter. These differences may appear but slight, but to anyone who 

 sees a row of the two insects, they will, I feel sure, appear sufficient 

 to convince him of their real distinctness " (' Entomologist,' vol. xiii., 

 pp. 225-226, and <Ent, Mo. Mag.' vol. xvii., p. 115). 



