NOTES ON' Cor.KoPTKKA. 33 



and rugged, the holes are hardly perceptible until they have been pushed 

 some distance by the industrious little worker, who throws out periodi- 

 cally small mounds of the gnawed wood, which look like tiny heaps of 

 saw-dust accidentally dropped at irregular intervals upon the trunk. 

 If the bark and liber be stripped off, these burroAvs will be found to 

 run horizontally through the bark to the cambium-layer, but when 

 the insect feels the greater resistance of wood beneath, it turns off and 

 eats its way through the cambium-layer, always in a longitudinal 

 direction, for a distance of several inches. Copulation is performed, I 

 believe, invariably, in a remarkable situation : the ^ insect being in 

 the outer air, and the 5 within the entrance of her burrow. I have 

 very often found both sexes at the end of the burrow, but do not think 

 they copulate there. The eggs are rarely laid before the middle of 

 May, and sometimes not till the first half of July, but this depends 

 greatly upon the severity or otherwise of the spring. 



Under favourable circumstances, there are often as many as a 

 hundred and twenty larvaj in one family, and this fact becomes serious 

 to anyone who has noticed the great numbers of these insects that 

 may be seen flying in the early spring sunshine around a dozen pines, 

 felled to form a clearing. I have never personally found this par- 

 ticular insect in a standing tree, but that it does occur there, is beyond 

 doubt. So abundant are they sometimes that Ratzeburg noticed'"'' a 

 hundred parent borings (which are generally upon one side only of the 

 livimi tree) in a space two feet long, and, upon another occasion, fifty- 

 six larvae within five inches. Each larva bores for about three inches 

 before turning to a pupa. Now, if one takes fifty-six larv;e in a space 

 of five inches, and each bores some three inches during its life, it is 

 obvious the poor host has a very scanty chance of escaping destruction, 

 since it is the cambium-layer, destroyed by the insects, through which 

 the sap circulates, and which, becoming hard, adds to the bulk of the 

 tree, consequently without this layer the tree dies. Having completed 

 their ecdyses, the little pests emerge about July or August, but their 

 depredations are not yet at an end : they next fly to the fresh shoots at 

 the end of each twig, bore a small aperture, about four inches from the 

 apex, and, making their way up the centre, gorge themselves upon the 

 luscious sap, and so kill the shoot, which is blown to the ground, 

 breaking at the entrance-hole of the insect, by the first gale of Avind. 

 In fir woods the earth is often carpeted Avith these fallen shoots, in 

 each of Avhich, about the beginning of September, may be found the 

 cause of the injury. Later the borer escapes through a hole at the 

 end of its burroAV, and hundreds may sometimes be found hybernating 

 at the base of trunks in the neighbourhood, comfortably ensconced 

 just beneath the soil or moss, half concealed in the bark, and in mild 

 weather they will gnaw promiscuously in their immediate vicinity. This 

 particular species never occurs in fir Avoods at any great altitude, and 

 almost inA-ariably on Finns si/lirfitris. though once or tAvice in 

 Pomerania it Jian been taken from Abicfi curdsa, though it probably 

 occurred there accidentally. 



Hi/lastes! ater is a someAvhat similar species, not only in appearance, 



but in habits and choice of environment, though I have never noticed 



it attack the same tree. The larA'a, pupa, and imago have occurred to 



me in one stump, as early as March 11th, and I Avas much interested at 



* J. T. C. Eatzebufg, in Die Forst-Insecten, p. 211. "" 



