INDIRECT INJURIES CAUSED BY INSECTS. 93 
tribe of Geocorise Latr.; but it seems very difficult to conceive how an 
insect that lives by suction, and has no mandibles, could destroy these 
lants so totally. 
When the wheat blossoms, another marauder, to which Mr. Marsham 
first called the attention of the public, takes its turn to make an attack 
upon it, under the form of an orange-coloured gnat, which introducing its 
long retractile ovipositor into the centre of the corolla, there deposits its 
eggs. These being hatched, the larva, perhaps by eating the pollen, pre- 
vent the impregnation of the grain, and thus in some seasons destroy the 
twentieth part of the crop.* 
Much mischief is also sometimes done by a species of Thrips (T. cerca- —— 
tina Haliday), a minute insect, often abundant on flowers, which, insinu- 
ating itself between the internal valve of the corolla and the grain, inserts its 
rostrum into this last, and causes it to shrivel*; and according to Vassali 
Eandi$, as quoted by Mr. Haliday, the same species also attacks the stem 
at a still earlier period, causing the abortion of the ears, and sometimes to 
such an extent that in 1805 (in which year the wheat in England, also, 
suffered apparently from this cause) one third of the wheat crop on the 
richest plains of Piedmont was destroyed by this seemingly insignificant 
little insect.* 
One would think, when laid up in the barn or in the granary, that wheat 
would be secure from injury ; but even there the weevil (Calandra granaria), — 
in its imago as well as in its larva state, devours it; and sometimes this 
pest becomes so infinitely numerous, that a sensible man, engaged in the 
brewing trade, once told me, speaking perhaps rather hyperbolically, that 
they collected and destroyed them by bushels: and no wonder, for a single 
pair of these destroyers may produce in one yeur above 6000 descendants. 
There are three other insects that attack the stored wheat, which are more 
injurious to it than even the weevil. One is a minute species of moth 
(Linea granella L.), of which Leeuwenhoek has given us a full history 
under the name of the wolf. Another is a species of the same genus, at 
present not named, which, as we are informed by Du Hamel, at one time 
committed dreadful ravages in the province of Angoumois in France. The 
third is Trogosita caraboides, a kind of beetle, the grub of which, called 
Cadelle, Olivier tells us did more damage to the housed grain in the 
southern provinces of France than either the weevil or the wolf.® 
In this place, too, must be noticed the caterpillars of a moth (Caradrina 
cubicularis), which Mr. Raddon told me were found in such quantities ina 
wheat-stack near Bristol, when taken down to be thrashed, that he could 
have gathered them up by handfuls, and they had done much injury to the 
grain. 
Here I may just mention a few other insects which devour grains that 
are the food of man, concerning which I have collected no other facts. 
The rice-weevil (Calandra oryz@) is very injurious to the useful grain after ~~ 
which it is named ; as is likewise another small beetle, Lyctus dentatus F. 
(Sylvanus Latr.); and an Indian grain, called in the country Joharre, which 
1 Tipula tritici K., belopging to Latreille’s genus Cecidomyia. —Marsham and 
Kirby in Linn. Trans, iii, 242—245. iv. 225—239. v.96—110. 
2 Kirby in Linn. Trans. iii, 242. 3 Mem. Acad, Turin, xvi. Ixxvi. 
4 Haliday in Lntom. Mag. v. 444, 5 Oliy. ii, n, 19, 3, 4 
® Trans. Ent. Soc. Lond. ii. proc, xlii. 
