172 INDIRECT INJURIES CAUSED BY INSECTS. 



its turn to make an attack upon it, under the form of an 

 orange-coloured gnat, which introducing its long retrac- 

 tile ovipositor into the centre of the corolla, there depo- 

 sits its eggs. These being hatched, the larvae, perhaps by 

 eating the pollen, prevent the impregnation of the grain, 

 and so in some seasons destroy the twentieth part of the 

 crop a . 



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, speak- 

 ing perhaps rather hyperbolical ly, 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 gmnella), happily not much if at all known 

 in this country ; 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 com- 

 mitted 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 . 



a Tipula TriticitK., belonging to Latreille's genus Cecidomyia. (See 

 above, p. 28. note 3 .) Marsham and Kirby in Linn. Trans, iii. 242-5. 

 iv. 225-39. v. 96-110. b Oliv. ii. n. 19. 3-4. 



