616 Prof. Westw@8d on the minute Diptera 
agree with Cecidomyia tritici in the habit of feeding 
upon the young grain, and not within the stem of the 
plant like the Chlorops lineata. Hence we learn that, 
instead of the housed grains being uninjured, as was 
stated, each fly must have destroyed one of the oat-grains, 
remaining within the scales until the crop had been 
housed. Hence, too, we also learn that if it were possible 
to submit the grain, as soon as threshed, and before 
being housed, to the action of a degree of heat sufficient 
to kill the flies without injuring the grains, the chances 
of next year’s crop of oats being freed from the ravages 
of the insect would be greatly increased. 
The insect before us appears to me to be identical with 
the Musca avene of Bjerkander, and with Oscinis atricilla 
of Zetterstedt (‘Ins. Lapponica,’ col. 781, No. 11*). 
The latter is the only one of the sixty species of the 
genus described by Meigen, Fallen, or Zetterstedt, with 
which it can be compared. 
O. atricilla is stated by Zetterstedt to have the greatest 
resemblance to O. pusilla,+ which, I believe, is identical 
with the Oscinis vastator of Curtis, differmg in being 
blacker and less metallic in colour, and in having the 
anterior tibize and tarsi blackish brown, whereas they are 
black in my insects. 
The ‘ Transactions of the Linnean Society of London’ 
(vol. ii., p. 76, 1794), contain a memoir entitled “‘ Some 
Account of the Musca pumilionis of Gmelin’s Edition of 
the ‘Syst. Nature.’ By Wiliam Markwick, Esq. With 
additional remarks by T. Marsham, Esq.” Early in 
spring some fields of wheat near Battle appeared to be 
much blighted, the injury being caused by a small grub 
lodged in the very heart of the stem just above the 
root; from some of the diseased plants placed in a 
flower-pot, and covered with gauze, several small flies 
were produced. The plants thus attacked threw out 
* Oscinis atricilla, Zetterstedt, ‘Insecta Lapponica,’ col. 781, 
Novy 
Tota nigra, antennarum seta pedibusque concoloribus, alis hya- 
linis, halteribus albidis. Mas, foem. 
Magnitudo et summa precedentis (O. pusilla) similitudo, a qua 
non differt nisi colore magis atro, vix metallice nitente, et pedibus 
totis nigris, tibiis tarsisque anterioribus nigro-fuscis. 
+ O. pusilla, Zett., l.c., col. 781, No. 10. Subsnescenti nigra 
tota, antennarum seta concolore, tibiis anterioribus tarsisque 
omnibus pallidis ; alis hyalinis, halteribus albis. Mas, foem. 
