90 



LETTER VI. 



INJURIES CAUSED BY INSECTS. 

 INDIRECT INJURIES continued. 



HAVING endeavoured to give you some idea of the mode in which 

 insects establish and maintain their empire over man and his train of de- 

 pendent animals, I shall next call your attention to his living vegetable pos- 

 sessions, whether the produce of the forest, the field, or the garden; 

 whether necessary to him for his support, convenient for his use, or mi- 

 nistering to his comfort, pleasure, and delight: and here you will find 

 these little creatures as busily engaged in the work of mischief as ever, 

 destroying what is necessary, deranging what is convenient, marring what 

 is beautiful, and turning what should give us pleasure into an object of 

 disgust. 



Let us begin with the produce of our fields. Bread is called "the staff 

 of life : " yet should Divine Providence in anger be pleased to give the 

 rein to the various insects which, in the different stages of its growth, 

 attack the plant producing it, how quickly would this staff be broken I 

 From the moment that wheat begins to emerge from the soil, to the time 

 when it is carried into the barn, it is exposed to their ravages. One of its 

 earliest assailants in this country is that of which Mr. Walford has given 

 an account in the Linnean Transactions, taking it for the wire-worm ; but, 

 as Mr. Marsham observed, not correctly, it being probably the larva of 

 some coleopterous insect, perhaps of one of the numerous tribe of J3ra- 

 chyptera or rove-beetles, which are not universally carnivorous. This 

 animal was discovered to infest the wheat in its earliest stage of growth 

 after vegetation had commenced ; and there was reason to believe that it 

 began even with the grain itself. It eats into the young plant about an 

 inch below the surface, devouring the central part ; and thus, vegetation 

 being stopped, it dies. Out of fifty acres sown with this grain in 1802, 

 ten had been destroyed by the grub in question so early as October. 1 

 Other predaceous Coleoptera will also attack young corn. This is done by 

 the larva of Zabrus gibbus, both with respect to wheat and barley. In the 

 spring of 1813 not less than twelve German hides (Hufen), equal to two 

 hundred and thirty English acres, of wheat, were destroyed by it in the 

 canton of Seeburg, near Halle, in Germany; and Germar (who, with 

 other members of the Society of Natural History at that place, ascertained 

 the fact) suspects that it was the same insect described by Cooti, an 

 Italian author, which caused great destruction in Upper Italy in 1776. 

 Not only is the larva, which probably lives in that state three years, thus 

 injurious, but, what one would not have expected, the perfect beetle itself 

 attacks the grain, both of wheat and barley, when in the ear, clambering 



1 Linn. Trans, ix. 156161. 



