86 Second Report on Economic Zoology. 
The Larch and Spruce Aphis. 
( Chermes abietis-laricis.) 
The larch is very frequently damaged by this pest in different 
parts of the country. Buckton records in 1871, that “the woods 
in some parts of Surrey were so covered with the myriads of white 
tufts spun by these insects that they appeared as if starch had been 
dusted over them. Many boughs died back, and in the autumn the 
trees looked as if they had been scorched.” 
The presence of this pest ( Iccricis ) is very easily detected when on 
the larch by the white wool excreted by them, and by the galls when 
on the spruce ( abietis ) ; larch in some cases looking as if covered with 
snow. Trees of all ages are attacked by this pest, which sucks out the 
sap from the leaves, and also the young bark. Schlich figures a 
characteristic way of damage in the larch, the needles bending over 
where the Chermes is feeding, and the area around it turning pale. 
This elbowing of the needles is not, however, always noticeable. I 
have frequently seen trees quite white from this pest, and yet 
not a single leaf bent; this was the case in a specimen sent from 
Northampton during the past year. This larch pest is also known as 
the Larch Bug and Larch Blight. According to Buckton,* Chermes 
laricis is confined to the larch, but Dreyfus and others have almost 
conclusively shown that this species and the Spruce Gall Aphis 
{Chermes abietis) are alternating forms of one and the same species. 
The form on the larch ( C . laricis) is agamic only, but on the spruce 
there is always one annual sexual generation (C. abietis), separated 
from the preceding sexual generation by a series of agamic forms, 
which it appears may remain on the spruce or may migrate to the 
larch. 
Life-history of C. abietis-laricis. 
The female Chermes laricis pass the winter under the bark of the 
trees and appear in spring. This so-called “ queen aphis ” hibernates 
under the leaf scales, often several together, and presents a curious 
shrivelled, almost dead appearance, and generally resembles the 
colour of the bark. As soon as the buds begin to swell and the 
spring approaches, they also swell and then throw off their skin, 
which is retained by the Aphis some days, being attached by three 
long spirally-coiled hairs. Later, after another moult, the queen 
becomes silvery white with pale brown tubercles. When fully grown 
* Mono. Brit. Aphides, iv., p. 38. 
