RHYNCHOTA 193 



not uncommon on coniferous trees. There are several species, 

 which differ slightly in details of structure, and inhabit different 

 kinds of conifers. 



Chermes is aphis-like, but has relatively short antennae 

 and legs. The dorsal surface is covered with perforated 

 shields, from whose pores waxy threads are often exuded 

 (these do not appear till after the first change of skin). The 

 wingless asexual forms have very long and flexible piercing 

 beaks, and three-jointed antennte, while the winged forms 

 have the beak short, and the antennje five-jointed. The beak 

 is also short in the sexual wingless forms. In winged Chermes 

 the fore wings are large, the hind wings very small. 



The life-history of the Spruce Chermes may be supposed 

 to begin in spring, when there may be found here and there 

 on the bark of the fir a minute yellow or greenish wingless 

 insect, thickly covered with a waxy exudation, which looks 

 like wool. Sometimes two or three are found lurking, together 

 in one crevice. These are the hibernating females. As soon as 

 the shoots begin to push, the female Chermes selects a young 

 shoot, pierces the base of the bud with her long ' proboscis, 

 and sets up the distorted growth known as the false cone. 

 As summer advances the cone enlarges till it is as big as a 

 filbert, or even bigger. In June it is bright green, composed 

 of regularly arranged scales, and looking much like a true 

 fir-cone, from which, however, it can be distinguished by the 

 foliage-leaves which grow from it. The hibernating female, 

 after three changes of skin, lays her eggs and dies. Each egg 

 has a transparent waxy envelope, which is drawn out at one 

 end into a thread for attachment ; about 200 may be laid by 

 a single female. The larvae, when hatched, attach themselves 

 to the false cone, and apparently creep into cavities enclosed 

 between its scales. In July or August the cones are hard 

 and ripe ; the scales shrivel, and the cavities open, disclosing 

 numerous larvae, which are at first green, afterwarids reddish ; 

 when closely examined, they are found to possess wing- 

 rudiments. After a final change of skin, the wings are fully 

 expanded, and the migrating females are complete ; they are 

 larger than the hibernating females, and reddish or orange- 

 yellow in colour. Some of them remain on the spruce, and 

 lay eggs, from which hibernating females are produced ; others 

 migrate to larches, and lay eggs whose product is again a 



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