94 



FOREST ENTOMOLOGY. 



doubtless during this initial boring operation that copulation takes 

 place. She tlion makes her burrow proper, which is from 1 to 

 4 inches in h'ugtli, and tlierein deposits from 100 to 160 eggs. 

 This ojieration is said, as a ride, to take al)()ut three weeks to 

 com]ilctc. 



The markings are very characteristic, more especially when the 

 mother-gallery is comparatively short. The mother-gallery is straight 

 and single-armed (fig. 84). Taking, therefore, the middle of the gallery 

 as a centre, it may be noted that the; larval galleries do not quite 



^.lf3?iSi^t<1 



t 



Fig. Si.—Marldncis 0/ Siiolytus destructor 

 in hark of Knglish elm. 



Fig. 85. -,S7(o »■(•"-; " exit- 

 holes" of same. 



run at rigid angles with the mother-galhiry, l)nt pt)int slightly towards 

 the extreme ends ; and as we look towards either end of the mother- 

 gallery, it is noticeable that the angle becomes more acute, and con- 

 sequently the spaces between the extreme ends of the larval galleries 

 widen. Hence if a line were drawn all round the extreme ends of 

 the larval galleries, it would form an oval-shaped figure, with the lines 

 radiating from the centre to the outer edge. Fig. 85 shows the holes 

 whence the beetles have emerged. 



The beetle (fig. 80) is about fV of 'iii iii^^'li i" length. The thorax is 

 black and shining, and the abdomen light-brown. The beautiful sharp 

 contrast of colour is a conspicuous feature, and thus afTords a rapid 



