1890. J 125 



easy, and knowing, as we all do, that which Mr. Bankes calls " the 

 unparalleled range of variation both in colour and markings" of 

 mercurella, and after Mr. Bankes' assertion (Ent. Mo. Mag., ante p. 8) 

 that these species are in reality abundantly distinct, " none of the 

 numberless varieties of mercurella ever showing the peculiar characteristics 

 of cratcsgella" it is certainly astonishing to find that Mr. Bankes 

 should so naively confess that after all the easiest way is by the eye 

 alone. Here I quite agree with him. No doubt there are specimens 

 which are perfectly easy to be picked out, but the difBculty lies not 

 in the " types " of each so-called species, but in those intermediate 

 specimens in which, as Mr. Bankes himself is forced to own, the dif- 

 ferences he points out " become modified as the opposite extremes of 

 variation are approached." Mr. Bankes, in introducing his table of 

 the nine points of distinction, says, " in every instance I believe that 

 several of the points will be found to hold good." Bearing in mind 

 his strong assertion, which I have previously referred to, will he not 

 assist us by saying which these points are, or by even naming one single 

 point which always holds good ? The absence of the knowledge of any 

 such point has hitherto been our stumbling block, and if Mr. Bankes 

 will but remove it, he will render great assistance. 



My own series of mercurella and cratcegella consist at present of 

 138 specimens from very varied localities, but the more specimens I 

 see the more I feel inclined to doubt whether the certain conviction 

 of their non-identity which I used to feel some years ago is not 

 erroneous. It is very probable that I am wrong in the suggestion that 

 cratoegella may be a chalk form, but I should like to hear from those 

 who take it commonly whether it affects any particular soil, or whether 

 it is as indifferent to soils as mercurella. 



55, Lincoln's Inn Fields, W.C. : 

 Afril \Uh, 1890. 



DESCRIPTION OF THE LAEVA OF CATOCALA FRAXINL 

 BY G. T. POKRITT, F.L.S. 



On the 2nd of July, 1886,1 received two larvse of Catocala fraxini 

 from Mr. E. C. Ivy, of Southport. One of them was nearly adult, 

 the other about half grown ; the former I describe as follows : — 



Length, nearly 3 inches, but slender in proportion. Head broader than the 

 second, but a little narrower than the third, segment, flattened in front and slightly 



