1909. 1 205 



Of Dolerus we have a much longer list of species, and I have 

 found it by no means easy to tabulate their differences satisfactorily, 

 nor to make up my mind as to the claim of various forms described — 

 often from single specimens — as distinct species to rank as such. 

 Mr. Cameron (as well as Hartig and Zaddach) has called attention to 

 the presence of most striking characters in the ? saws and their 

 supports, and I have carefully studied all the figures of saws, &c., 

 given by these authors, and compared them with microphotographs 

 taken by myself from specimens mounted in balsam. As a result of 

 this comparison, I feel satisfied that the value of the saw-characters 

 for discrimination, and also to some extent for grouping of the species, 

 can hardly be exaggerated. Zaddach's figures are truly admirable, 

 and of the seven given by him I can identify all quite confidently as 

 belonging to British species known to me, except that of his brevi- 

 cornis, and even as to the latter can say with certainty that it is not 

 that figured by Mr. Cameron under the name oblongus — which latter 

 species was at one lime doubtfully referred by Konow to brevicornis, 

 Zadd. At the same time 1 have thought it useless to introduce into 

 my Tables characters which can seldom be seen without dissection of 

 the specimens. It is certainly desirable, as Mr. Cameron suggests, 

 that Doleri should be so prepared that the saws can be examined, but 

 it cannot be expected that all collectors will be induced to do so, and 

 I must add that in bringing the saws to light there is danger of de- 

 stroying other characters hardly less useful, viz., those of the saw- 

 sheath, which will sometimes suffice of themselves for the correct 

 placing of an insect, and which should alwaj-s be taken into con- 

 sideration before finally deciding on its specific identity. 



As the easiness, and sometimes even the possibility of naming a 

 Dolerus for certain, depends a good deal on the manner of its pre- 

 paration, I venture to make a few remarks on this point— the result 

 of many sad experiences on my part in dealing with other people's 

 insects and my own. (1) A Dolerus should never be so pinned as to 

 obliterate the characters of the thorax above ; and of all places into 

 which a pin can be thrust the worst from this point of view is perhaps 

 the most usual, viz., at or near the junction of the mesonotal lobes 

 with the scutellum. The best plan known to me for avoiding damage 

 to the thoracic characters is to mount the insect without piercing its 

 dorsal surface at all, either (as Konow always did lately) running a 

 very fine small pin into, but not through, the thorax from below, or 

 else fixing it with a very small drop of gum astride upon a narrow 

 strip of card or celluloid, and then in both cases " staging " the whole 



