RAVAGES OF MAGGOTS. 255 



corn, and grasses, and are thence destructive to gar- 

 dens, fields, and meadows. They prevailed in the 

 neighbourhood of Edinburgh, and other places in 

 Scotland, in the spring of 1800, when they laid 

 waste whole fields of oats and other grain."* 



In many districts of England these insects cut off 

 a large proportion of the wheat crop, particularly, it 

 would appear, when it had been sown on clover leys. 

 " In the rich district," say Kirby and Spence, " of 

 Sunk Island, in Holderness, in the spring of 1813, 

 hundreds of acres of pasture have been entirely de- 

 stroyed by them, being rendered as completely brown 

 as if they had suffered a three months' drought, and 

 destitute of all vegetation except a few thistles. A 

 square foot of the dead turf being dug up, 210 grubs 

 were counted on it ; and, what furnishes a striking 

 proof of the prolific powers of those insects, last year 

 it was difficult to find a single one."t 



It is worthy of remark that the mandibles of these 

 destructive creatures, which are claw-shaped and 

 transverse, do not act against each other as is usual 

 among insects, but against two other pieces which are 

 immoveable, convex, and toothed, — as if the under- 

 jaw in quadrupeds were divided into two, and should 

 act vertically on the two portions of the immoveable 

 upper-jaw thrown in between them. 



The maggot of a minute fly of the same family, 

 known by the name of the wheat-fly {Cecidomyia 

 Tritici, Kirby), is frequently productive of great 

 damage in the crops of wheat. Its history was first 

 investigated by Marsham, and subsequently by Kirby, 

 and several other intelligent naturalists. The parent- 

 fly is very small, not unlike a midge (Culicoides 

 punctata^ Latr.), of an orange colour, and wings 



* Elements, ii. 267. f Intr. i. 318, note. 



q2 



