i es ee? 
THE ENTOMOLOGIST. 
No. 140.] MARCH, MDCCCLXXYV. [Price 6d. 
Life-histories of Sawflies. Translated from the Dutch of 
Dr. 8S. C. SNELLEN VAN VOLLENHOVEN by J. W. May, Esq. 
(Continued from p. 28.) 
NEMATUS ABBREVIATUS, Hart. 
Imago: Hartig, Blatt-und-Holzwespen, p. 205, No. 38. 
Larva hitherto undescribed. 
Nematus fusco-niger, crassus, abdomine contracto, prothorace 
supra, trochanteribus, femorum apice, tibiis tarsisque 
anterioribus luteis, tibiis tarsisque posticis variegatis. 
The genus Nematus of Jurine, which was, in fact, first 
precisely defined by Hartig, is, like all the divisions of the 
last-named author, made to depend principally on characters 
derived from the course of the nervures of the wings, and the 
genus so defined contains groups differing considerably in 
the structure of the body: some are slender, and more or 
less attenuated; and to this group belong N. Salicis and 
N. septentrionalis, and similar species, the larvee of which have 
twenty legs, seldom, however, making any use of the last 
pair, and have the habit of almost incessantly alternately 
raising and depressing the abdomen. Others, to which our 
species Abbreviatus belongs, are short and compressed in 
form, and apparently proceed from larve having only eighteen 
legs. If this obtained as a rule, which I am far from being 
able to assert, it would, I think, tend to prove that divisions, - 
depending exclusively on differences in neuration, are artifi- 
cial and not natural; it would, however, be rash to attach 
too much weight to an observation made upon the metamor- 
phosis of a single species. 
VOL. VIII. oH 
