STOMAPHLS QUERCUS. 63 



and this action is continued during the visits of the 

 black ant, Formica fuliginosa, which by trooping np 

 and down the branches of the trees often betrays the 

 presence of the Aphis. The winged form appears to 

 be exceedingly rare. Neither "Walker, Passerini, nor 

 myself have ever met with a living specimen. Kal- 

 tenbach, however, describes it, and he notices that 

 there are winged and apterous males, both of which 

 are of diminutive size. 



This Aphis is very scarce in England, but at one 

 time it seems to have been somewhat common in 

 France and Germany. It has been described with 

 some particularity by Reaumur * and Bonnet, and 

 afterwards by Kaltenbach. It is not, however, in- 

 cluded in Koch's list of Lachnince. 



Mr. Walker communicated to me the following note 

 on this insect in answer to my inquiries : 



" I think Tugall was the first person to discover 

 Aphis quercus in England, and he mentioned it to 

 Stephens, who published a notice thereon about 1847 ; 

 but I do not find it mentioned in the list of writings 

 of the latter author. About that time Tugall directed 

 me to an oak near Dulwich, where I fonnd it ; and 

 some years after, the late Mr. Alfred Smee told me of 

 an oak at Weybridge, where I found it again, and 

 subsequently I met with it at Finchley. I have only 

 named, not described it, as Stomaphis, though I think 

 that it is sufficiently peculiar to be separated from 

 Lachnus. The male is mouthless, or rather it has no 

 rostrum." 



Bonnet describes an Aphis which I think must be 

 referred to the above insect. He says it is remark- 

 able for the magnitude of its trunk. " Le puceron de 

 chene — c'est I'elephant des pucerons," and as large 

 as an ordinary fly. It attaches itself to the branches of 

 the oak, which "on commence anoircir." La couleur 

 " brun fence terne sur le dos, pen luisant sous le 

 ventre;" legs, antennse, and trunk, "rouge maron." 

 * ' Mem. des Insectes,' ix, p. 334, torn, iii, 1734. 



