18 BRITISH APHIDES. 



long, yellow-green. Wings long, very hyaline, with 

 pale-yellow veins and greenish stigmata. These have 

 darker inner margins. Cubital vein without any fork. 

 It does not anastomose with the cubitus, but is cut 

 short as in Schizoneura. Third and fourth veins 

 proceed almost from the same point of the cubitus. 

 Lower wing with a single faint oblique vein. 



The ringed antenna! joints are not noted by Koch, 

 but Kaltenbach describes Vacuna as always annu- 

 lated in these organs, " alle zart geringelt," and gives 

 a rough figure in accordance with this character. 



Passerini considers Vacuna betulce to be identical 

 with V. alni, which, in Italy, infests the ends of the 

 branches of Alnus incanus. 



Thelaxes betulce is noted by "Walker in his * Cat. of 

 Hemipt.,' vol. iv, p. 1052. Elsewhere he says, " it is 

 sometimes common in the Isle of Man." 



