The Zoologist — January, 1868. 1041 



species of larva arc required to constitute one species of imago ; or, 

 secondly, that two species of Lepidoptera, entirely different in their 

 preparatory stages, become precisely similar in their adult state. I 

 accept the latter conclusion, and fully believe that pairs of species 

 may in a thousand instances be so exactly alike in the imago state as 

 to defy every effort to differentiate them. To all human perception 

 this pair of species, when examined in their ultimate state, are abso- 

 lutely identical. 



2. Boarmia rhomboidaria and B. perfumaria. — I have had the 

 pleasure of minutely examining, and most carefully describing, the 

 larvae of these two species. The differences between the two possess 

 the invaluable attribute of constancy ; neither ventures over its natural 

 boundary line, whether in form, colour or food. Arrived at maturity, 

 their similarity is so great that entomologists generally refuse to per- 

 ceive any difference between them ; but I cannot go quite so far as to 

 say that none exists : those who like myself have repeatedly bred both 

 from the egg, and closely scrutinized the adults as they entered on 

 their winged existence, have observed differences which at the moment 

 seemed to separate them, although soon to be lost after the moths have 

 taken wing. The rhomboidaria of the Vienna Catalogue, of Hiibner, 

 Haworth, Duponchel, Guenee, &c, is correctly described by Guenee 

 as cendre-jaundlre, the dark cinereous ground-colour of the wings is 

 suffused with a yellowish tint, while in the rhomboidaria of Stephens 

 the colour is more uniformly cinereous and without any yellow tinge 

 whatever. I should characterize this insect as very smoky, perfmn aria : 

 in accordance with its metropolitan habitat, it seems to be saturated 

 with smoke : Guenee gives other characters of distinction, although he 

 treats perfumaria only as a variety ; he says it is a little larger, the 

 fore wings are a little more pointed, and a little more prolonged at the 

 tip ; the pectinations of the antenna? are rather longer and are not 

 appressed so closely on each other. Several writers, in a recently- 

 established and highly scientific journal devoted exclusively to 

 Entomology, also allude to both species in a manner that implies 

 perfect familiarity with them. 



3. Cabera pusaria and C. rotundaria. — In this instance we labour 

 under a double difficulty : in the first place, C. rotundaria, in all its 

 states, is very imperfectly known ; and, in the second place, there is 

 but little inclination exhibited to acquire a more perfect knowledge. 

 In almost every cabinet certain individual insects are set apart from 

 Cabera pusaria and are labelled " rotundaria." Haworth was the first 



SECOND SEPJES — VOL. III. D 



