190 



FOREST ENTOMOLOGY. 



Chehmes laricis (Hartig). 



This species, considered as distinct for the practical man, and 

 the remaining species of Chermes differ from the preceding, in- 

 asmi;ch as vlridis is gall-forming, and those about to be considered 

 protect themselves by a woolly covering. The evidence of the 

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

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

 reveals the al)ode of the queen-mother. With regard to Chefiiies 



Fig. 272. — Chtrnies laricis on hurl nflan-h. 



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

 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 ^ (fig. 272). This is no doubt 



' Mr Theobald, in correspondence, saj's : " You cannot trace a single one on the 

 stems 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." 



