328 



FOREST ENTOMOLOGY. 



Chermes laricis (Hartig). 



This and the remaining species of Chermes differ from the preced- 

 ing, inasmuch as abietis is gall-forming, and those about to be con- 

 sidered protect themselves by a woolly covering. The evidence of 

 the presence of abietis cannot in a general way be recognised by the 

 naked eye until we find a white speck in late spring. This speck 

 reveals the abode of the queen-mother. With regard to Chermes 

 laricis, on the other hand, considered as a distinct species, the queen- 



Fig. 301. Chermes laricis on hark of larch. 



mothers may be found throughout the whole of the winter months on 

 the stems of young infected trees, their presence being indicated by 

 the cottony covering on the stems 1 (fig. 301). This is no doubt 

 the main harbourage, but many specimens may also be found hiber- 

 nating just underneath the leaf-scales.' 2 



1 Mr Theobald, in correspondence, says : " You cannot trace a single one on the 

 sterns in South England, where laricis swarms. The trunk aphis is found in 

 Lincolnshire. There is no doubt it is different, and that there are two allied 

 species." 



2 The two forms viz., those on buds and those on bark are probably quite 

 distinct. The latter is termed C. riridis by some entomologists. 



