184 



THE ENTOMOLOGIST. 



viii. 18()) as attacking young trees, but in the instance near 

 Isleworth the trees had grown to their average height, and 

 were about a foot in diameter. Probably in this case the 

 damp locality of the spot where the trees had grown, and 

 were laid, facilitated the boring operation, especially on the 

 lower side of the timber next the grass, which was the part 

 chiefly affected. The beetles appeared to attack the smooth 

 surface or any of the slight fissures indifferently, as a com- 

 mencement point for their burrows, whilst the elm Scolyti 

 have been noted as usually taking advantage for their start 

 of the cracks or crevices of the rough elui bark. 





Workings of Hylesinus i-jiaxim. 



The work was begun about the 19lh of April, the beetles 

 being then wandering in great numbers over the timber, 

 till an appropriate spot being found and the boring com- 

 menced, the beetle continued firmly at its work irrespective 

 of any disturbance. In four days the Hylesini had dis- 

 appeared, the only signs of their presence being the ejected 

 results outside of their borings inside the bark. The progress 

 was very slow, in captivity the advance of the beetle being 

 only about half its own length in from ten to twelve hours ; 

 in natural circumstances, rarely more than half an inch in 

 the ten days after first observation of the insects. The 

 work was begun by a single beetle drilling a circular bore 

 just large enough to allow of its passage, where it was 

 shortly joined by its companion — the pair presumably working 



