Classification of Insects: Coleoptera. 169 



ical range of species, their migrations, the causes that favor or 

 hinder their increase, and the means for diminishing their damages. 



673. In a recent publication of the U. S. Eutomological Com- 

 mission, prepared by Prof. A. S. Packard, Jr., of Providence, E. I.,' 

 there has been collected a summary of all that had been previously 

 published concerning the forest-insects of the United States. We 

 will present some of the more important facts of this Report, con- 

 cerning the more injurious of these insects. As it will be necessary 

 to refer to the orders under which insects are classed, they may be 

 first concisely defined : 



(1.) Coleoptera (Beetles). 



674. These are insects. with jaws, two thick wing-covers, in a 

 straight line on the top of the back, with two filmy-wings, which are 

 folded transversely. They pass through four stages of life — the 

 egg, the larvae or grubs (generally provided with six legs), the pupa, 

 and the perfect insect. In most cases the greatest damage is done 

 in the larva state. The coleoptera are divided into several great 

 divisions, the principal of which are as follows : 



675. (a.) The Scarabceidce, embracing an immense number of 

 species, known as ground or dung-beetles, tree-beetles, etc. Their 

 larvas do great damages to the roots of trees, and the perfect in- 

 sects to the leaves and twigs. They fly in the evening, and may be 

 destroyed to some extent by shaking them off from the trees in the 

 morning, first spreading cloths before jarring the trees. 



676. (6.) The Lucanidce, or stag-beetles, which are distinguished 

 by the great size and peculiar form of their upper jaws. The grubs 

 of the larger kinds are said to remain six years before changing to 

 a perfect insect. They live in the trunks and roots of trees, and 

 bore into the solid wood. 



677. (c.) The Bupestridoe, or saw-horned beetles, so called because 

 the tips of the joints of their antennae project more or less on the 

 inside, somewhat like the teeth of a saw. They are often brightly 

 colored, and have usually a hard shell and an oblong form, tapering 

 behind. They keep concealed at night, and are abroad only by 



' Bulletin No. 7. Insects Injurious to Forest and Shnde Trees, 1881, p. 275. 

 This Cominission consists of Professors Charles V. Riley, of the Depart- 

 ment of Agriculture at "Washington, Dr. A. S. Packard, Jr., of Brown Uni- 

 vftrsity. Providence, and Prof. Cyrus Thomas, of Carbondale, 111. 



