8 4 
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. strobilobius. 
They are so closely allied that we are, as Burdon remarks, 
“ reduced to a sole difference in habit for distinction between 
the two species. If the Alatae migrate, the species is Ch. 
strobilobius ; if not, it is Ch. lapponicus .” 
We have thus far considered four species, Ch. abietis and 
its double Ch. viridis , in which the Fundatrices are seated at 
the base of the bud; and Ch. lapponicus , with its double 
Ch. strobilobius , in which the Fundatrices are seated on the 
bud. There still remain Ch. orientalis Dreyfus and its 
double Ch. sibiricus Cholod., in which the Fundatrices are 
seated on the stem a little distance below 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 find 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. ulmi 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, 
