THE LARGE LARCH SAWFLY. 47 
are side by side on the under surface at the hind end of the 
sawfly. The adult sawflies do not attract much notice, but if 
examined it will be seen that they do not have the narrow waist 
characteristic of the wasps, but that the base of the abdomen is 
broadly joined to the thorax. The adults, in nearly every case, 
are harmless, save that, of course, they lay theeggs. The larve 
are very characteristic: they are caterpillars, with more than 
sixteen legs (the caterpillars of the genus Zyda, troublesome on 
fruit and forest trees, have eight legs, six in front and a pair 
behind; and the corn sawfly, Cephus, if included under Zenthredi- 
nide, would be another exception), and they feed in the great 
majority of cases exposed ; a few, however, live in galls, or mine 
or burrow in plant-tissue. Dr Sharp reckons that nearly 400 
species have been found in Britain, and amongst these are 
species troublesome in gardens, and to fruit, and in agriculture. 
Six or seven genera contain species of importance in forestry, of 
which Lophyrus (see Leaflet 103), ZLyda, and Mematus are the 
most important. 
The species of the genus Vematus that have relation to forestry 
affect, amongst broad-leaved species, the willow chiefly. The 
interesting, and sometimes injurious, caterpillars of /Vematus 
septentrionalis, besides feeding on willow, attack also the leaves 
of birch, hazel, alder, and mountain ash. On the larch, besides 
Nematus Erichsont, the large larch sawfly, I notice later, for 
comparison, Vematus laricis, the small larch sawfly. 
DESCRIPTION OF WVematus Erichsont. 
Adult.—The adult sawfly measures up to 2 inch, or a little 
over, in length, and in spread of wings just less than an inch. 
The ground colour is black. The head and thorax are black ; 
the first joint of the abdomen is black; then follow joints 
coloured red ; the end of the abdomen again being black. The 
mouth parts, the two front pairs of legs, except at the part next 
to the thorax, and the upper parts of the femora of the hind legs, 
are reddish or reddish-yellow. The tibiz are yellowish or pale 
in the upper parts. The antenne are nine-jointed and some- 
what thick, and taper towards the apex. With a lens the head 
and thorax are seen to be sparsely and finely pubescent, and the 
thorax is markedly punctured. The wings are glassy and 
slightly clouded below the stigma. 
