1912.] 235 



middle of the dorsvim. More iisiially the red is quite unbroken on at least 

 three segments). Unfortunately quite a number of other species, or supposed 

 species, have almost exactly the same arrangement of colour. Some of these 

 one learns by practice to separate from coquehertii ? (at least to one's own 

 satisfaction!) by smaller size, more extensive pale markings on head and 

 thorax, a certain difference of tint in the red on the abdomen, paler coloration 

 of the legs (especially the hind tibice), &c. But the best advice I can give to 

 collectors who wish to learn the " points " of coquebertii 9 is to secure, if 

 possible, a series of specimens that have been taken in company with the 

 umnistakeable S S , f-nd to study these carefully side by side with others that 

 they have reason to suspect of belonging to other species. Yet I do not believe 

 that much real progress in determining the true specific relations of such closely 

 similar and admittedly most variable forms is likely to be made, till much more 

 material has been collected than is at present available to show what males and 

 what females really belong together, and how far the characters on which our 

 supposed species rest are really constant throughout long series of specimens 

 bred together or taken abiindantly at the same time or under the same 

 particular circmnstances. Till this has been done, I believe that it is a 

 mere beating of the air to argue whether this or that name applied by this 

 or that old avithor to such and such a combination of colours in a single 

 sex (for i-eally this is all that these descriptions amount to) be the older, 

 and therefore the one to be adopted. First let us know what species really 

 exist with us, and then we may consider how we are to call them. I do not 

 make these remarks with the desire of awakening discussion of a thorny 

 subject ; but to explain why, since King positively tells us that the insect 

 which he called "coquebertii" was a S with the exceptional alar neiiration 

 above referred to, and since the ? ? found with such S S cannot, as yet at 

 least, be shown to have any character of even approximately equal value, I 

 should continue to call the species coquehertii, Kkig, even if I thought it 

 probable that some older description of a Tenthredopsis 9 ^^ the works of — 

 say — Fabricius or Lepelletier really referred to it. 



3. T. excisa, Thoms. This is one of the few cases where both sexes of a 

 Tenthredopsis can be identified even by a beginner with reasonable certainty by 

 a few simple and obvious characters. 1. The white clypeus is very distinctly 

 emarginate at the apex, in such a way that it may be said to be divided into a 

 pair of rovmded lobes. (In oui- other species, so far as I know them, if the 

 clypeus be sinuated inwards at all, the emargination is very shallow and 

 extends throughout the whole length of its apical margin — there is no appear- 

 ance of a pair of lateral lobe-like projections). 2. The tegulte are cleai'-white, 

 and for that reason very conspicuous ; nuich more so than in most species, 

 where, if not black, they are usually at least a little grey or brown or yellowish. 

 It is rather a small species. The ? abdomen is coloured in all my specimens 

 like that form of coquebertii ? in which there is a black line bisecting the red 

 dorsTun. (In excisa, however, the red is somewhat paler, I think, than in coque- 

 bertii). The head and thorax are black, but adorned copioiisly with white. 

 The (J is very similar, but the black streak on the red part of the abdomen is 

 sometimes obsolete, and when present seems less sharply defined ( — a vague 

 clouding, not a distinct line or row of spots !). 



