32 BRITISH APHIDES. 



tennce rudimentary and composed of three joints only. 

 Rostrum very short. Head broad, and joined to the 

 body without the intervention of any well-marked 

 thorax. Abdomen large and deeply ringed. The 

 posterior end is occupied by a remarkably developed 

 male apparatus, which by compression under weak 

 glycerine gives rise to a plentiful stream of sperma- 

 tozoa. The alimentary canal is very short, and the 

 nutritive organs are very simple. The cavity of the 

 abdomen is taken up almost entirely by the sperm- 

 capsules; but I am unable to satisfy myself as to the 

 correct number of these last united into a single duct. 



Several other small, wingless Chermes were dispersed 

 within the cells of the pseudo-galls, but I could not be 

 sure of their sex. Inasmuch as they contained no 

 visible ova, they might have been immature males. 

 It is likely that one male visits many cells in succes- 

 sion, and thus the smaller sexed females, if bred within 

 the cones, would be fitted for their subsequent ovipo- 

 sitorial duties. 



The above description affords yet another example 

 of the apparent rule that a recurrence to a fecundated 

 ovum is the ultimate step taken before the pheno- 

 menon of a true fresh birth. Thus, as the males have 

 at last been found in Coccus and in Cynips, so now 

 Chermes offers no exception. The degraded characters 

 and minuteness of this sex have been the chief causes 

 of their being overlooked hitherto. 



It will be noted that in all the true Aphides hitherto 

 described the oviparous females are wingless, and pro- 

 bably will always be found to be such. 



There is, however, a departure in Chermes from 

 Aphis proper. The queen Aphis in Pemphigus, Schizo- 

 neura, Tetraneura, &c, is the constructor of the gall she 

 inhabits. She surrounds herself with vegetable growth, 

 and in the cavity which she produces she stores her 

 young, and their pricking increases the size of the gall 

 already formed. 



In Chermes ahietis we see, according to the observers 



