84 BRITISH GALLS 



wool, and lighter colour. They become reddish towards 

 the end of egg-laying, and their eggs are dark green. I 

 cannot separate the Alatae from those of Ch. strohilohius. 

 They are so closely allied that we are, as Burdon remarks, 

 " reduced to a sole diflference in habit for distinction between 

 the two species. If the Alatae migrate, the species is Ch. 

 strohilohius ; if not, it is Ch. lapponicus." 



We have thus far considered four species, Ch. ahietis and 

 its double Ch. viridis, in which the Fundatrices are seated at 

 the base of the bud; and Ch. lapponicus, with its double 

 Ch. strohilohius, in which the Fimdatrices are seated on the 

 bud. There still remain Ch, orientiUis Dreyfus and its 

 double Ch. sihiricits Cholod., in which the Fundatrices are 

 seated on the stem a little distance helow the bud. Very 

 little is known respecting Ch. orientalis and Ch. sibiricus in 

 this country. Burdon observed the galls caused by one of 

 them on the Oriental Spruce {Picea orientalis) at Cambridge 

 in 1907, but failed to find the hibernating Fundatrix. My 

 experience at Haslemere in 1909 was very similar. I found 

 numerous galls on Picea sp. late in July, but as this gall 

 opens very early. May and the first fortnight in June, the 

 occupants had left. Curiously, I have since failed, after 

 most careful examination, to fi^d any Fundatrices and new 

 galls on this tree. 



Whether the six forms above alluded to are true species 

 or merely varieties remains to be proved. According to 

 Cholodkovsky, they are valid species ; but, as Burdon 

 suggests, possibly some of them may eventually be shown 

 to be nothing more than biologic forms. 



Certain Aphidae of the genus Schizoneura give rise to some 

 very striking galls. Schizoneura. ultni attacks Elm leaves. 

 The afflicted leaves curl downwards and inwards, forming 

 a scroll gall of a pale yellow colour. These galls are 

 not uncommon in summer and autumn in many districts. 

 There are seven generations in the life-cycle of this Aphis. 

 The wingless queen or Fundatrix is of variable colour. 

 She attacks the young leaf, causing it to blister and curl. 



