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XXIII. Obfervations on the Infers that infejted the Corn in the Tear 1795 

 In a Letter to the Rev, Samuel Goodenough, LL. D, F. R, S, Tr, L. S. 

 By Thomas Mar/Jjam, Efq, Sec, L, S. 



Read May 3, 1796. 



Dear Sir, 



TOWARDS the end of July lad, a friend of mine [Mr. Long) 

 who had the management of a farm in Hertfordfhire, was 

 telling me that an infect had made its appearance among the 

 wheat, which threatened to do much mifchief; that it was found* 

 in many inftances, to have attacked one, two, or more grains in an 

 ear; and that it was difcoverable by thofe grains appearing yellow, 

 or as it were ripe, while all the remaining grains in the fame ear 

 were perfectly green.— I defired that gentleman to bring me up 

 fome of the difeafed ears, which he did ; and I found them exactly 

 as he had defcribed them. — On opening thofe grains that feemed 

 difeafed, I found in many of them an orange-coloured powder, and 

 in feveral, one or two very minute larva, differing in colour, from a 

 yellowifh white to a deep yellow. They were too minute for exa- 

 mination by the naked eye ; but by applying a deep magnifier I 

 perceived them to be the larvae of a fmall mufca, and to refemble very 

 much thofe aphidivorous larva: that produce one particular family 

 of the mufc<z. They were thick at one end, and gradually dimi 

 nifhed to a point at the other, where the head was fituate. They 

 extended and contracted themfelves at pleafure ; to which was 



added 



