1903.] 47 



HELP-NOTES TOWARDS T[IE DETERMINATION OF BRITISH 

 TENTHREDINIDM, &c. (2). 



BY THE BKV. F. D. MORICE, M.A., F.E.S. 



The neiiration of a Saw-fly's wing looks so complicated till it is 

 understood, that I thinic I had better begin by showing it reduced to 

 its simplest type, i. e., with such nervures only as belong not to parti- 

 cular Genera but practically to all Families. 



I take then, to start with, a rather simple front-wing— that of an 

 Empht/tus; omit certain nervures which are not universally found in 

 the Saw-flies; dislinguish longitudinalhi from transversely running 

 nervures by using thick single lines for the former and thinner double 

 ones for the latter; and tlius produce the following Figure. 



Fig. 3.— Upper Wing of a Saw-fly (simplified). 

 C 



b 



Nervures in the above Fig. (Koiiow's nomenclature).* 

 Longitudinal " Adern " (=" veins," vence). 



a f k eosta ; b f subcosta ; c t v medius ; d x braeliiua ; e g humerus ; 



h i k radius ; 1 o y cubitus. 

 Transverse " Nerven " {t= "nerves," nervi). 



i n, j p cubital nerves ; I q discoidal nerve ; m s, o u medial nerves ; 



r w areal nerve ; t x anal nerve. 



I am afraid that even this simplified figure will to a novice seem 

 rather appalling ; but really it is not difficult to understand with a 

 little explanation. 



The first thing to be done is to realize the course of the lonyifu- 

 dinnl nervures =^ the "veins" — the thick single lines. It will be 

 seen that they are much longer than the transverse = the " nerves." 



* The synonymy of these nervures in different authors is excessively confusing (e.g. , the cubitus 

 of Hai-tig is the subcosta of Thomson and Koiiow, while the cubitus of Thomson is Kouow's 

 medius). To discuss the matter at length is outside the purpose of this paper ; and I shall simply 

 adopt Konow's nomenclature en bloc. Certain changes, I must own, would to my mind simplify 

 and so far improve it ; but that is a matter of opinion, and I believe I do better to accept the 

 names as I find them, and only to enter into the nomenclatiire question just so far as is necessary 

 to make Konow's system intelligible to readers who have studied these insects only with the 

 works of English authors to guide them. 



