APHIDID^E. 309 



Tribe LACHNINiE. 



We now approach the second tribe of the family, known as 

 Lachninse. The venation is the same as in the preceding tribe, but 

 the antennae are six -jointed. This character as revealed by the 

 microscope is important to the systematist. To the economic ento- 

 mologist, however, there is no general character as revealed by the 

 injuries in the forest which can suggest a marked line of classifica- 

 tion. The term Lachnus means " woolly," and this character is well 

 pronounced in the genus Phyllaphis, which is often very abundant 

 on beech ; but unfortunately many members of the genus Lachnus 

 have no wool. 



Genus Pterocallis. 



The characters of this genus may be described as rostrum short and 

 stout ; antennae shorter than in Callipterus, the difference in length 

 being specially conspicuous in the apterous form ; six-jointed, but the 

 sixth joint has a break in the middle, which might on indistinct 

 examination be mistaken for a seventh joint. Cornicles small and 

 stout. Wings shorter and narrower than in Callipterus, and most 

 beautifully clouded ; hence the term Pterocallis is derived from the 

 Greek, and means beautiful wing. 



Buckton describes three species as belonging to this genus, all of 

 which are arboreal in their habits namely, Pterocallis alni, on alder ; 

 P. juglandicola, on the walnut-tree (Juglans regia) ; and P. tilia, 

 on various species of lime, which, however, is so abundant on the 

 ordinary lime-tree (Tilia europea) that it may be taken as typical of 

 the genus. 



er 



Pterocallis tilia (Linn.) 



The apterous viviparous female is of a uniformly lightish-yellow 

 colour, with most beautiful light -red eyes. The antenna?, more 

 especially in the young stage, are light and dark, the basal portion 

 of each joint being light in colour, and the apical portion of the same 

 joint being very dark. The contrasting colours therefore make the 

 antenna? rather beautiful objects. 



The winged viviparous female is of a uniformly light colour on the 

 under surface of the body, and on the upper surface she is of a 

 yellow colour, with short dark bands reaching half-way across the 



