238 Rev. Mr. Kirby'j H'spry of 



rate of not quite two and a half grains to an ear; and in twenty ears 

 of red wheat, twenty-nine grains were deftroyed, which is nearly 

 at the rate of one and a half grains to an ear- Take the whole to- 

 gether, and the proportion will be about two grains in an ear, which 

 I iuppofe may be about a twentieth part of the produce, and would 

 make a difference of at lead: five coomb in the crop in this field. 

 The white wheat in this inflance was mod expofed to the attack of 

 the infeft ;— whether this be generally the cafe, muft be determined 

 by future experiments upon a more extenfive fcale. Lead mifchief 

 ieemed to be done on the South fide of the North hedge; but no 

 part efcaped wholly— not an ear I examined but what had fuftained 

 fome injury. From the field that I have been fpeaking of 1 went 

 to another, which was fown later in the Autumn : in this I found 

 fcarcely any of the larvae; but it was very much infefted by the 

 jfphis, called in Mr. Markwick's letter above-mentioned the Dol- 

 phin*. The fame fpecies of Aphis is fufneiently common upon 

 barley and oats, as well as wheat : I found very few of thefe in the 

 firft field. The red gum, which is undoubtedly a kind of Fungus, 

 appears to me totally unconnected with the infects that infefr. the 

 wheat: in the field where I found an infinity of the larvae 

 of the TipuJa Trili'd, and Thrips pbyfapus, I fcarcely found any 



* Poffibly this may be the Aphis Aven* of Fabricius : but as he has given no defcription 

 of it, I cannot bepofitive ; I (hail therefore defcribe it under the name of 

 A. gratiaria, viridis, cauda bifeta, fetisgeniculifque pedum nigris. 



Aphis aveme. Fab. Sp. Inf. ii. p. 386. n. [7. Gmel. torn. 1. part. iv. p. 2206. 

 n. 52. Fill. Ent. Eur. 1. p. 551. n. 50? 



Caput flavidum uti antennarum articulus primus. Oculi nigri. Abdomen obovatum 

 cauda aculeata. Pedes lividi, tarfis geniculifque nigris. 



Habitat in tritici et hordei fpicis, avenaque panicuKs, 



florets 



