HYMENOPTERA SAW-FLIES, ETC. 



91 



being terminated by the ovipositor. The wings are over two inches 

 in expanse, and the legs are yellow. 



The male (fig. 182) is smaller than the female, and with compar- 

 atively long antenna?. The abdomen is flattish and brown through- 

 out, except the first segment, adjoining the thorax, which is black. 

 The absence of the ovipositor is of course the salient point in quickly 



determining the sex. 



The legs are also darkish-brown. 



Sirex j u venous, Linn. 



The habits of this insect are almost identical with the preceding 

 species. There appears, however, to be a difference of opinion 



Fig. 1 84. Sirex juvencus (female), reduced. 



fir 



Fig. 1S3. Spruce timber injured by Sirex juvencus. 



a, shows transverse section of timber ; 6, shows 



longitudinal section of timber. 



Fig. 1S5. Sirex juvencus (male), reduced. 



amongst various writers as regards the trees upon which they are 

 found, and it is possible either species may be general feeders on the 

 trees named ; but so far as my observations go, I should say Sirex 

 juvencus on spruce and larch, and Sirex gigas on Scots pine and silver fir. 

 Fig. 183 is a representation of injuries done to the timber of spruce. 



The larvae are narrower and more elongated, and more of a dirty- 

 white colour. 



In general outline the female (fig. 184) resembles that of Sirex 



