Rev. F. D. Morice's Notes on Australian Sawflies. 263 



ought to be drawn from this fact, so I here content myself 

 with merely mentioning it. 



This difference in the number of its palpi, combined 

 with other characters which shall presently be noticed, 

 certainly justifies the treatment of Xyloperga, as a good 

 subgenus, and possibly as a good genus, though at present 

 I am not convinced that it is either necessary or desirable 

 to exclude it absolutely from Perga. Certainly some species 

 of the latter (e.g. the bella group) seem to me to have really 

 more characters in common with Xyloperga, than with 

 others (e.g. dorsalis, etc.) in whose company such an arrange- 

 ment would leave them. Therefore, in separating Perga 

 and Xyloperga in my Synopsis of the Genera above, I have 

 lather deferred to what I believe to be the opinion of more 

 competent judges of such questions, than followed any 

 conviction of my own. But. as to the other " segregations " ' 

 which have been proposed mostly on single characters 

 oil en insignificant, and sometimes cmite imaginary,* 

 such as the presence or absence of a distinct 1st cubital 

 nerve in the wings of certain species. I must claim liberty 

 to disregard them altogether, till the collection of more 

 material makes it possible to say for certain, whether or 

 no these characters (when they exist at all) are really 

 characteristic of any natural groups of species. So far as 

 I have been able to test them, I have always found them 

 either " individual," or absolutely non-existent ! So long 

 as a majority of the species are known only from single 

 specimens, and the total number of supposed species is 

 no larger than at present, I can see no advantage whatever, 

 and on the contrary considerable disadvantage, in pre- 

 maturely establishing and naming sections, which may or 

 may not correspond to real natural groups. On this kind 

 of work I venture to think that " the last word " was said 



* E. g. Leach says that /'. polita has only 3 cubital cells. This 

 is not really the case in his own Typical specimen, the 1st cubital 

 nerve being merely interrupted in the middle, but not absent; 

 and examination of other specimens shows that the aberration is 

 not specific, but individual. However, on the strength of Leach's 

 mistaken statement. Ashmead made polita, Leach, the Type of a 

 "new genus," which he characterised by the absence of the 1st 

 cubital nerve, and named " Pseudoperga." Perhaps, fortunately, 

 the same name had been already employed by Guerin ( 1845) and 

 Shipp (1894) to denote a different section of the genus, the Type 

 of which is lewisii, Westw. ; so that Pseudoperga, Ashmead. may 

 safely be ignored as a homonym. 



TEANS. ENT. SOC. LOXD. 1918. — PARTS 111,1V. (.MAR." 19) T 



