CORN APHIS. 63 



of the great numbers sent me were entirely brown throughout 

 all their stages, and without any of the green in the early 

 stage, or partial amount of green in the winged specimens, 

 which is characteristic of the true S. grcmaria.'^ They 

 corresponded more with the A. aveme, Fab., of which some 

 short description is given in Curtis's ' Farm Insects,' p. 500, 

 and leave the matter consequently in doubt whether this so- 

 called " Oat Aphis " is not a true, distinct species ; or, again, 

 whether these dark Aphides sent me were only a variety of 

 the variable common S. granaria ; or, again (following the 

 conjecture sometimes brought forward), whether there is a 

 change of colour in the insect with the change of food, — from 

 green whilst feeding on the leaves or stem, to the brown 

 colour when it has settled in the grain. 



Prevention and Remedies. — Dusting with lime, whilst the 

 Corn is still young and the Plant-lice spread about on it, has 

 been suggested as useful; and soot would be likely to do good, 

 it being a fertilizer, as well as disagreeable to the insects ; but 

 probably a dressing of any kind of manure that would 

 encourage healthy growth would be best. The nature of this 

 would depend on the soil, and state of the crop.t 



It has been noted that, when the crop was late, it suffered 

 severely ; when early, it suffered less ; whether this is always 

 the case does not appear, but it is likely, partly from the 

 leaves and ears having parsed the soft, delicate state in which 

 the Plant-louse can pierce them with its sucker, before the 

 insect appeared to attack them, and partly from the larger 

 and more vigorous plants being better able to bear attack 

 than the young ones. 



In a leading article of the ' Gardener's Chronicle and 

 Agricultural Gazette' for August 15th, 1868, it is remarked: — 

 " The Plant-louse in the hot summer of 1864 was, and is 

 again during the present hot season, a great pest. It mostly 

 affects the later Wheats, which in some cases are covered 

 with hundreds of these creatures, which can only live by 

 sucking out the juices from the ear ; hence early Wheats are 



* The following is a short general description of specimens forwarded from 

 Tabley Grange, Cheshire : — The youngest forms or " lice " were fawn or brown. 

 The pupse brown or chestnut-brown, with the fore body paler, and with a 

 greenish tint ; the wing-cases (which are at this stage appendages like little 

 fins or flattened spikes laid on the sides), were pitchy-black down the middle; 

 the honey-tubes pitchy. Winged specimens : Fore body chestnut or somewhat 

 yellow-fawn ; abdomen of a darker shade of chestnut, and eyes dark chestnut. 

 Wings glassy, not quite transparent, with yellowish nerves. 



f This would appear to be precisely a kind of attack which (until the Corn 

 grew too high) might be advantageously treated by fluid dressing, thrown by 

 the air-drill popularly known as the " Strawsonizer." The drenchings would 

 greatly injure the Aphides, and would push on a good growth of the plants. 



