516 CONIFER M. 



of its prevalence in his extensive plantations. It is pro- 

 bable, however, that it was introduced at a much earlier 

 period, or with the original plants, but that it remained 

 unnoticed so long as the trees were dispersed and few in 

 number, and its increase had not been encouraged by large 

 and dense plantations. As might be expected, its pre- 

 valence and effects have been most conspicuous in seasons 

 when the early growth of the larch has been suddenly 

 checked, or injured by heavy frost-fogs, or biting winds 

 in spring, for in such years the insect obtains an ad- 

 vantage during the check of vegetation, which the tree 

 does not so easily overcome. In winter the eggs of 

 the eriosoma, where numerous, may be detected even 

 by the naked eye, thickly crowded together around the 

 base of the buds, and in the small depressions and crevices 

 of the bark of the last year's wood, in the form of 

 small black grains. As spring advances these eggs are 

 hatched, and the female insects excluded soon give birth 

 to an innumerable living progeny, which, as the leaves 

 expand, spread themselves over the foliage, at first small 

 and black, but as they increase in size becoming covered 

 with a white, flocculent, cottony-looking substance, which 

 is produced from tuberculous pores upon the different parts 

 of their body, and the trees become clammy and black with 

 the honey dew, or excrementitious discharge of the insects 

 which live upon the resinous sap of the tree, pumped out 

 by means of a delicate tubular proboscis. Towards the 

 end of summer the males are produced ; these, in their 

 perfect or imago state, are furnished with wings, and 

 in autumn may be seen in thousands, flying actively about 

 the Larch plantations. For some years the appearance 

 of the eriosoma caused great alarm, and apprehensions 

 were entertained of its proving a serious objection to the 



