232 [October, 



11. — 0. pnndatuJus, Sturm. As this insect is slightly largei" 

 than the largest 0. rvfibarbis, and is metallic in colour on the upper 

 surface, it cannot readily be confounded with any of the species I 

 have discussed, while from the following forms it is readily dis- 

 tinguished by the rectangular hind angles of the thorax. The 

 oedeagus is most like that of 0. pnncticoUis, which species is, on the 

 whole, the one to which punctatulus conies nearest. 



The three larger species, 0. sahtdicola, Panz., 0. nhscurns, Fabr., 



and 0. rotundicollis, Fairm., are well enough known, so that I need 



only remai'k that the aedeagus is very similar in all of them, and 



differs but little from what we find in 0. rufibarbis and 0. brevicoUis. 



Brockenhurst : 



18th August, 1912. 



HELP-NOTES TOWAEDS THE DETERMINATION OF BEITISH 



TENTHREDINIBM, &c. (30.) 



BY THE REV. F. D. MORICE, M.A., P.E.S. 



TENTHREDOPSIS, Costa. (In Part). 



Any difficulties with which I have had to contend in previous 

 papers of this series appear mere trifles in comparison with those 

 which now confront me. It may seem strange that a genus like 

 Tenthredopsis consisting of fairly large insects, many of them by no 

 means rare, and almost always strikingly and to all appearance 

 veiy " characteristically " coloiired, should not long ago have been 

 broken up by systematists into well-defined groups and ' species,' 

 having each at least some one positive and constant ' differentia ' of 

 its own by which it might be identified with certainty. But as a 

 matter of fact, the more the genus is studied, the more doubtful does 

 it appear whether any (except a very few) of the characters on which 

 species have been founded in it are more than individual peculiarities 

 of particular specimens, or at most of local races. And I fear that 

 this is true not only of those old descriptions of so-called ' species,' 

 which make no pretence to be based on any differences except those of 

 colour, but of others whose authors have thoroughly realized the 

 extreme variability of coloration which may exist within the limits of 

 a single species in this genus, and have taken extraordinary pains to 

 supplement or supplant such colour-characters by others derived 

 from structure — slight differences in the length and thickness of 

 the antennae, or the calcaria, the greater or less development of the 



