G47) 
THE LARGE LARCH SAWFLY (NEMATUS 
ERICHSONI). 
By Eric B. Dunuop. 
Te Large Larch Sawfly belongs to the family Tenthredinide 
of the order Hymenoptera. In Europe it is found in the north 
and central portion of the continent, and in North America from 
Central Michigan to Labrador. 
MacDougall describes the female* as follows :—‘‘ She measures 
up to 3in., 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 
neat to the thorax, and the upper parts of the femora of the hind 
legs, are reddish or reddish-yellow. The tibie are yellowish or 
pale in the upper parts. The antenne are nine-jointed and some- 
what thick, and taper towards the apex. JWitia lens the head and 
thorax are seen to be sparsely and finely pubescent, and the thorax 
is markedly punctured. The wings are glassy and are slightly 
clouded below the stigma.” 
The male is very scarce; out of three hundred pups Prof. 
Hewitt secured only two. ‘The following differences in the sexes 
are noted by himt :—“ The male is smaller than the female. The 
terminal portion of the abdomen is broadly rounded. The legs are 
paler in colour than those of the female, and only a small portion 
of the distal extrenuties of the tibie of the third pair of legs is dark 
coloured.” 
The egg is white in colour, and measures just over a millimetre in 
length. The full-grown caterpillar measures three-quarters of an 
inch, or a little over, in length. It has a round, black, hairy head, 
with a single ocellus on each side. On the upper surface, all down 
the back, the colour is grey-green; the sides are lighter ; the wnder 
surface is yellowish-green. If a lens is used, there will be seen, on 
the abdominal segments, transverse rows of minute warts with 
* The ‘ Journal’ of the Board of Agriculture, October, 1906, p. 889. 
+ Ibid., December, 1908, p. 650. 
