1912.] 233 



tempora, the exact shape and sculpture of the vertical area aud 

 scutellum, the exact position of the " second recurrent nervure," and so 

 forth. I have pondered long and carefully over many elaborate diagnoses 

 published by Konow of his own species and those of other authors, 

 and cannot help seeing tliat they are often quite irreconcileable with 

 determinations kindly made by him for me of specimens in my own 

 collection. Had he lived longer, a meeting which we had planned 

 (and to which I have alluded in an earlier paper) might have removed 

 some of the hesitation which I now feel as to quoting and relying upon 

 these determinations. Moreover, several of the Tenthredopsis-iorma 

 described as British by Mr. Cameron are, I believe, unknown to me 

 altogether; others of them again I seem to recognise in specimens 

 which I possess or have examined, but am unable to form any opinion 

 of my own whether or no they deserve to be recognised as ' species,' 

 and in some cases he appears himself (in his Vol. iv) to modify or 

 abandon his earlier opinions about them. 



On the whole, I believe that I should create more confusion than 

 I should remove if I attempted at present to construct such Tables 

 for the determination of British Tenthredopsis spp., as I have di-awn 

 up for our other genera. Instead, I will only point out the characters 

 by which, in certain cases, I am able myself to arrive at a confident 

 opinion as to the identity of a particular specimen, and in others to 

 form some sort of conjecture — often a very dubious one — on the same 

 subject. This may, perhaps, be most conveniently done in the form of 



NOTES ON PARTICULAR SPECIES. 



1. T. litterata, Geoffr. sec. Konow. ( = nassata, Thorns. = thomsoni, 

 Konow olim.). This species comprises a number of our largest forms, differing 

 very widely in colour as far as the ? .i* are concerned, but hardly, if at all so, 

 in the S S . One form of the ? — not a very common one — has more or less 

 the coloration of the ^ , but the others are utterly unlike it, and are only 

 known for certain to belong to it by having been found repeatedly in the act of 

 pairing with it. Formerly they were treated without hesitation as distinct 

 species ; and various S c? more or less agreeing with one or other of them in 

 colour were, on that ground only and (as we now know) quite incorrectly, 

 assigned to it by variovxs authors. The character by which, whatever their 

 colour, all these 9 ? may be recognized is the form of the " hypopygium," i.e., 

 the curiously modified ventral plate which immediately precedes the base of 

 the saw-sheath. This is larger than in other species, and excised very deeply 

 at its apex, so that the latter becomes shai-ply ' bidentate.' In all oiu- other 

 species, the apex of the hypopygium is ' entire ' and subtriangular. 



The cj of litterata has a pale whitish-yellow head and thorax, more or less 

 largely marked above Avith black, its abdomen is of a reddish orange, with a 



