On the Wheat-midge. 39 



Nos. 1 and 2.- — These were obtained at the same time, and 

 show that more are contained in a bushel of the dust from the chaff 

 than in that from the dross. As there must be many more 

 bushels of the former than of the latter, it proves that a very great 

 majority of the larvae are blown out with the chaff. Had the 

 chaff been selected from near the machine only, the difference 

 would have appeared more striking. 



Nos. 3 to 6. — Obtained at another barn, clearly show that the 

 majority of the larvae fall within about a yard of the machine, and 

 that it would be unnecessary to sift the chaff which falls beyond 

 3 yards in order to obtain them. 



No. 7. — Obtained from a third barn, abounded with the midge 

 to a much greater extent than the former samples. But this 

 sample was searched more carefully than the others, with the aid 

 of a pocket lens, which may partly account for the very large 

 number detected. I do not know how many bushels of dust 

 might have been obtained by sifting the chaff of a whole harvest- 

 ing, on any one of these farms, but was informed that it would 

 have amounted to several. The usual practice is to throw this 

 dust aside, either upon the floor of the stable or on the muck in 

 the yard ; and it is supposed that any insects or seeds it may con- 

 tain will be destroyed by the process of fermentation. It is very 

 possible that many are destroyed in this way, but I do not doubt 

 that vast numbers must escape. I have therefore suggested the 

 propriety of always burning this dust, as not only afibrding a 

 ready means of destroying these and other insects, but also of 

 getting rid of a number of minute seeds of weeds. A slight 

 alteration in the regular routine of farm practice would be all that 

 would be necessary ; the chaff being sifted immediately after the 

 dressing of the wheat, instead of at the time when it is given to 

 the cattle. If it should hereafter appear that these encased larvae 

 never turn to the fly state, and consequently that the practice here 

 proposed would be needless, I should still suggest the propriety 

 of its being generally adopted ; I have learnt within a very ievf 

 days that it is constantly resorted to in one part of this country 

 where the farming is of a superior character. The practice 

 would doubtless be found useful in promoting that wholesome 

 cleanliness from weeds which is so essential to the perfect success 

 of all crops. 



From some observations I made in the neighbourhood of St. 

 Albans, I am inclined to think there are more species than one of 

 these midges which infest the wheat ; and that possibly different 

 species may be limited to particular districts — I judge merely from 

 some slight differences which struck me in the character of the 

 larvae obtained from thence. I have received the larvae from the 

 North of Ireland and from Shropshire, and have now found them 



