CORN AND GRASS APHIS. 85 



this feeds on many kinds of Grass, from the unusual virulence of the 

 infestation, and also from there being a slight difference in the 

 disposition of the black markings on the green abdomen of the 

 winged females from what is considered the typical colouring, I 

 thought it possible a variety might be present, and therefore sub- 

 mitted my doubts and also specimens to Mr. G. B. Buckton, F.R.S., 

 our great authority on Aphides, who kindly replied as follows : — 



" An examination of the Aphides you sent to me leads me to the 

 conclusion that the pest is the Siyhonoplwra granaria of Kirby, that is, 

 S. cerealis of Koch and Passerini, and A. avencR of Schr. The only 

 hesitation would seem to depend on the more or less distinct barring 

 on the abdomen of the winged females. The spots are named by 

 authors, but not the bands. 



"iS. granaria feeds on many kinds of grasses, as well as the true 

 cereals. I think it not improbable that the description of food modifies 

 colour (I find it so in Indian Aphides); and again, some of your speci- 

 mens had only traces of these transverse bands. Hot weather gives 

 redder tinges to the later broods. This may be noticed also in AjMs 

 rapcR. The presence of several parasitic Hymenoptera (Ephedriis of my 

 plate) confirms me in my opinion, and they show the farmer that these 

 flies are still looking after his interest." — (G. B. B.) 



These various points I entered on at the time in my reply to 

 Messrs. Finney's enquiries ; but as this early form of attack, whether 

 to corn crops still in the blade, or to fields of growing Grass, necessarily 

 differs so much in locality from the damage caused later on to corn 

 ears, or to seed-heads, as possibly to admit of some remedial application, 

 I give below a part of my letter of May 31st with some additions : — 



"I have carefully examined your 'Green Fly' specimens in winged, 

 pupal, and also in larval state from very first production, and I do not 

 see that there is any reason to doubt that they are the Aphis (Siphono- 

 phora) granaria, sometimes known as cerealis. I should not like to 

 speak quite positively, because this Aphis varies at times so very much 

 in colour that it may be red, green, brown, or yellow, and it is known 

 under several names ; but, taking a common-sense view, I think it is 

 the common Corn and Grass Aphis. 



"Besides, what may be distinguished as corn, such as Wheat, Oats, 

 Barley and Rye, this kind of Aphis is known to infest many kinds of 

 grasses, some of these of the customarily cultivated kinds, as some of 

 the Poas or ' Meadow Grasses,' Eough Cocksfoot, and other kinds of 

 less agricultural value, or none at all, as various kinds of Holcus, or 

 ' Soft Grasses,' the Soft ' Brome Grass,' the very common field-path 

 and roadside growing Wall Barley Grass, the Hordeum rmtrinum, the 

 Avena fatua, or Wild Oat, and others. We do not, so far as I am 

 aware, know certainly in this country where the Corn and Grass 



