INDIRECT INJURIES CAUSED BY INSECTS. 93 



tribe of Gebconsae Latr.; but it seems very difficult to conceive how an 

 insect that lives by suction, and has no mandibles, could destroy these 

 plants so totally. 



When the wheat blossoms, another marauder, to which Mr. Marshara 

 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 larvae, perhaps by eating the pollen, pre- 

 vent the impregnation of the grain, and thus in some seasons destroy the 

 twentieth part of the crop. 1 



Much mischief is also sometimes done by a species of Thrips (T. cerea,' 

 Una 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 2 ; and according to Vassali 

 Eandi 3 , 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. 4 



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 (Calandragranaria), 

 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 year 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 

 (Tinea 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. 5 



In this place, too, must be noticed the caterpillars of a moth (Caradrina 

 cubicularis), which Mr. Raddon told me were found in such quantities in a 

 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. 6 



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 oryzas) 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., belonging to Latreille's genus Cecidomyia. Marsham and 

 Kirby in Linn. Trans, iii. 242245. iv. 225239. v. 96 110. 



2 Kirby in Linn. Trans, iii. 242. 3 j\f em . Acad. Turin, xvi. Ixxvi. 

 4 Haliday in Entom. Mag. v. 444. 5 Oliv. ii. n. 19. 3, 4. 



6 Trans. Ent. Soc. Lond. ii. proc. xlii. 



