10 INSECTS INJURIOUS TO VEGETATION. 



many winged or adult insects are provided. The piercer is some- 

 times only a flexible or a jointed tube, capable of being thrust out 

 of the end of the body, and is used for conducting the eggs into 

 the crevices or holes where they are to be laid. In some other 

 insects it consists of a kind of scabbard, containing a central 

 borer, or instruments like saws, designed for making holes wherein 

 the eggs are to be inserted. The sting, in like manner, consists 

 of a sheath enclosing a sharp instrument for inflicting wounds, con- 

 nected wherewith in the inside of the body is a bag of venom or 

 poison. The parts belonging to the abdomen of larvae are vari- 

 ous, but are mostly designed to aid them in their motions, or to 

 provide for their respiration. 



An English entomologist has stated, that, on an ayerage, there 

 are six distinct insects to one plant. This proportion is probably 

 too great for our country, where vast tracts are covered with 

 forests, and the other original vegetable races still hold ^possession 

 of the soil. There are above 1200 flowering plants in Massachu- 

 setts, and it will be within bounds to estimate the species of 

 insects at 4800, or in the proportion of four to one plant. To 

 facilitate the study of such an immense number, some kind of 

 classification is necessary ; it will be useful to adopt one, even in 

 describing the few species now before us. The basis of this 

 classification is founded upon the structure of the mouth, in the 

 adnlt state, the number and nature of the wings, and the transfor- 

 mations. The first great divisions are called orders, of which the 

 following seven are very generally adopted by naturalists. 



1. — CoLEOPTERA (Beetles). Insects with jaws, two thick 

 wing-covers meeting in a straight line on the top of the back, 

 and two filmy wings, which are folded transversely. Transfor- 

 mation complete. Larvae, called grubs, generally provided with 

 six true legs, and sometimes also with a terminal prop-leg ; more 

 rarely without legs. Pupa with the wings and the legs distinct 

 and unconfined. 



Many of these insects, particularly in the larva state, are very in- 

 jurious to vegetation. The tiger-beetles (Cicindeladc^), the preda- 



* See the Catalogue of Insects appended to Professor Hitchcock's Report on the 

 Geology, Mineralogy, Botany, and Zoology of Massachusetts. 2d edit. 8vo. 

 Amherst. 183.5. 



