26 BRITISH APHIDES. 



It is not yet quite clear if the queen-mother dies 

 outside of the developing gall ; leaving thus the young 

 which hatch from her eggs to enter these chambers 

 alone ; or whether she accompanies them into their 

 retreat. De Geer says that while the formation of the 

 gall proceeds, the old pine-louse dies (he does not 

 say where) of her infirmity, " die alte Tannenlaus aus 

 Entkriiftung stirbt." 



On the other hand, I have commonly found a wing- 

 less Chermes surrounded with young pupa?, and quite 

 enclosed by the walls of the chambered cone. 



This insect I consider to be the original queen- Aphis; 

 and if she be such, the encystment would be in perfect 

 accordance with the nidification of the females of 

 Pemphigus, Tetraneura, and the like. On the other 

 hand, this hatching outside the gall is in accordance 

 with Miss Ormerod's observations,* who remarks, in 

 her useful Manual, " with regard to the larva? that 

 were hatched outside presently becoming tenants of the 

 inside of the gall there is no doubt, . . . but I believe 

 that a minute slit opens along the upper part of the 

 sutures that mark the division of the swollen leaves, 

 and that through these openings the larva? creep into 

 the chambers within." 



By the irritation of the larva? the cells increase in 

 size, and finally become large enough to contain from 

 twenty to fifty insects in each chamber; their rostra 

 being plunged into the substance of the cell, and all 

 their heads being turned outwards and towards the 

 opening ; that is, the larva? all radiate from the centre of 

 the cone. As before noted, the queen Chermes may 

 be found within, surrounded by her progeny, which, 

 niter undergoing several moultings of skin, develop 

 their wing-cases. Eventually all, without exception, 

 become pupa?. 



A quantity of mealy matter lines these chambers ; 



* E. A. Ormerod, 'Manual of Injurious Insects,' p. 242. I tliink 

 fm-tber observation is desirable as to tbis question of encystment. — 

 G. B. B. 



