On Deep Draimiifj. 
131 
the shallow drains, which were 2 feet 6 inches deep, were laid in 
solid clav. There can, therefore, be no difficulty in accounting 
for the lower stratum bleeding the soil both more perfectly and 
more quickly than the shallower drains. The deep drains were 
also executed at a very moderate cost when the price of the 
pipes — viz. 305. for the 1^ inch, and 40j. for the 3 inch per 
thousand — is considered, as appears from the following state- 
ment : — 
£. s. d. 
Cutting and filling drains . . . 10 10 0 
Cost of pipes . . . . .850 
7 acres, at 21. \3s. "id. per acre . . £18 15 0 
JOSIAH PaRKES. 
May 27, 1845. 
XI. — Ohservations on the Natural History and Economy of vari- 
ous Insects affecting the Corn-Crops, including a Saw- Fly, the 
Hessian Fly, the Wheat-Midge, and the Barley-Midge. By 
John Curtis, F.L.S., Corresponding Member of the Imperial 
and Roj'al Georgofili Society of Florence, of the Academy of 
Natural Sciences of Philadelphia, «Scc. 
Cephus pygm^us — the Corn Saw-fly. 
In continuation of this subject from the last Number, I shall pro- 
ceed with the histories of those insects which infest the corn, and 
amongst them is one that is very abundant in this country, and 
with which I am well acquainted in its perfect state, having for 
many years observed the flies in corn-fields, occasionally in great 
abundance : yet I have never heard of its economy having fallen 
under the observation of any English naturalist or cultivator ; and 
it is to the dilig^ence and science of our continental neighbours that 
we owe the knowledge we possess of the habits of this interesting 
species. 
It is, however, by no means a recent discovery, for in 1819 
M. Dugaigneau, a skilful agriculturist of the department of the 
Loire, made known the metamorphoses of this species and the 
changes it produced in the wheat.* In his memoir he says, that 
having pulled up a quantity of the roots of rye at harvest time, he 
found some white larvae of a Sirex (pi. M., fig. 1) in the stubble. 
After the severe winter of 1812-13, he wished to see if the larvae 
had perished ; he therefore collected some stubble and found them 
* Annales de la Soc. des Sciences, Belles-Lettres, et Arts d'Orleans, v. 1, 
p. 121. 
K 2 
