HYMENOPTERA SAW-FLIES, ETC. 



18' 



plantations and report (see 'Journal of the Board of Agriculture,' 

 October 1906). I had in the same year found this species sparsely dis- 

 tributed in Northumberland. As this hitherto rare species has suddenly 

 appeared as a destructive insect, it affords a good case in point of the 

 necessity for the student being well grounded in general entomology. 



The damage done by this species consists in defoliating larch-trees 

 of various ages (see fig. 176) ; and as the injury is done whilst the trees 

 are vigorous, it is obvious that the increment is not only appreciably 

 affected, but the health of the tree may be considerably impaired. As 

 the larch is very susceptible to disease, it is important that everything 

 be done to obviate injuries of all sorts. 



Dr MacDougall thus describes the insect 



"Adult. The adult 



Fig. 176. Foliage of larch injured by 

 hirer o/Xematus Erielisonii. 



Fig. IT 



-Xematus Erielisonii. 



saw-fly measures up to | inch, or a little over, in length, and in spread 

 of wings just less than an inch (see fig. 177). The ground colour is 

 black. The head and thorax are black ; the first joint of the abdo- 

 men is black ; then follow joints coloured red, the end of the abdomen 

 again being black. The mouth parts, the two front pair of legs, ex- 

 cept at the part next to the thorax, and the upper parts of the femora 

 of the hind legs, are reddish or reddish-yellow. The tibiae are yellow- 

 ish or pale in the upper parts. The antenna? are nine-jointed and 

 somewhat 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 glossy, and slightly clouded 



below the stigma. 



