GALLS INDUCED BY PLANT-LICE 
79 
They resemble immature cones in size and shape, and are 
often alluded to as “ Pineapple ” galls. It has been dis¬ 
covered within recent years that several insects were at one 
time comprised under the name of Chevmes abietis , and even 
now there is much that is obscure concerning their life- 
history. 
In the true Chevmes abietis the life-cycle is confined to the 
alternation of two parthenogenetic generations on the Spruce. 
The larva hatched from an egg in autumn pierces a bud or 
its vicinity with its long proboscis, and thus firmly anchors 
itself for the long winter sleep. These larvae, or fundatvices , 
as they are often termed, may be easily found in winter 
by carefully examining the base of the shoots with a good 
pocket-lens. They are a dirty-yellow colour. In spring, 
about April—but the time depends upon meteorological con¬ 
ditions—without moving its position, the Fundatrix begins to 
suck, and attains maturity in about a month. It undergoes 
three moults, one every ten days or thereabouts. As soon 
as it begins to suck, and not before, precocious growth 
arises in the cells in the neighbourhood of the cambium, at 
the point where the apex of the deeply buried proboscis lies, 
and spreads rapidly outwards.- In the early stage there is 
little or no external evidence of altered growth, but a section 
cut through the bud will at once reveal it: the affected part 
looks bleached. Later the needles become swollen at the 
base. Being closely crowded they quickly begin to press 
upon one another, and four grooves result at the base of 
each needle. As elongation proceeds, the needles separate 
slightly, leaving a space above each. These spaces are 
afterwards occupied by the larvae. At this stage the gall 
is easily seen with unaided vision. In the meantime the 
Aphis has been steadily sucking and waxing fat, at the same 
time secreting much white, waxy, wool-like matter which 
covers her up, yet makes her presence more apparent. She 
has undergone her three moults (eedyses) and arrived at 
maturity. It is now about the second week in May, and 
she commences to lay her eggs, continuing to do so through- 
