18 
BRITISH APHIDES. 
moors itself to its feeding locality. Thus it is secured 
from dislodgment by the rough winds of early spring. 
Burmeister"^ pointed out a similar remarkable 
prolongation of the setee in the allied family of Coccus. 
Punctures never seem to be made by the rostral 
sheath. Under a lens, the leaf-feeding Aphides may 
be seen to search for a juicy spot with the tip of the 
rostrum. The piercing bristles then are inserted into 
the parenchyma, which would appear to be lanced in 
every direction by a sawing motion, which operation 
causes a plentiful flow of sap to the, wounded part. 
The points of the setse are not armed with barbs or 
serrations. 
THE THORAX. 
- This is composed of three principal parts, each of 
which bears its corresponding pair of limbs. 
The first segment, styled the Prothorax, Pronotum, 
or Neck-ring, is articulated to the head by a dense 
membrane, which shows itself often as a light- coloured 
band. This segment usually is small, and narrower 
than the head ; but in the winged Chermes the Pro- 
thorax is so considerably developed that it nearly equals 
the bulk of the Mesothoraw, and thus the insect has a 
somewhat overbalanced and clumsy appearance. This 
peculiarity is still more marked in the underside of the 
pupa of that species, where the coxge of the first pair 
of legs are far in advance of the position pointed out by 
the other coxae. 
The Prothorao) is occasipnally furnished with a strong, 
blunt tooth, on each lateral edge, the use of which is 
not known. t 
The Prosternum supports the Fulcra, to which the 
first pair of legs are articulated. 
The second thoracic segment is styled the Mesothorax 
Kaltenbacli, * Einleitung Terminologie der Pflanzenlause,’ p. xiii. 
t Plate B, figs. 3 and 4. 
