210 ENTOMOLOGICAL NEWS [xxxii, '21 



nations he has been guided by the works of such aphid students 

 as Choloclkovsky, Del Guercio, Mordwilko and others. Further- 

 more he wishes to acknowledge the many valuable suggestions 

 received from and the very kind courtesy extended by Mr. 

 Frederick Lainge of the Natural History Museum. 



Tribe LACHNINI Baker. 

 Sub-tribe Pterochlorina. 



1. Stomaphis quercus (Linn.). Walker; five slides (6 apterous 

 9$); "quercus; oak; Dulwich; Aug. 6-47. " 3 



This is the very characteristic species found throughout 

 Europe on oaks and the one for which Walker described the 

 genus Stowaphis* 



2. Pterochlorus longipes (Dufour). Walker; four slides (2 alate, 

 2 apterous, several immature 99); "roboris; oak; Southgate; July 

 5-47" (also July 27, Aug. 5 and Aug. 7, 3847). 



These specimens agree very well with Walker's description except 

 that the fourth and fifth antennal segments in the apterous females are 

 equal, while the third is equal to the combined lengths of the two, and 

 the rostrum extends only to the base of the third abdominal segment. 

 Walker states that the fourth antennal segment is "less than half the 

 length of the third; the fifth a little shorter than the fourth," and that 

 the rostrum reaches to the "hind hips." 



These differences are however of only minor importance. 

 There is no doubt in the writer's mind that this is the same 

 species that Del Guercio described as Dryaphis longipes (Du- 

 four), although Del Guercio makes no mention of the sen- 

 soria that appear on the third, fourth and fifth antennal seg- 

 ments of the alate female. As Del Guercio points out, Buck- 

 ton's Dryobius croaticus Koch is in all probability this same 

 species, but his Dryobius longipes (Dufour) is not this one. 

 That species belongs to the subtribe Lachnina of Baker, and 

 not to the Pterochlorina. and specimens in his collection appear 

 to be the same species as Walker's piccac. with the possibility 

 of an incorrect host plant determination, or they may be an un- 

 named species very closely related to that one. See the dis- 

 cussion under Dilaclinus piccac (Walker) No. 13 below. 



3 In each case the writer lias listed the number of slides, with the 

 number of specimens thereon, the collection in which they are found, 

 and the data which appear on the labels. 



"Walker, Francis. The Zoologist, vol. 28, p. 2000, .1870. 



