COLEOPTERA. 27 



while yet very young, consumed at least fifteen of these full-sized 

 grubs in one day, and of course would require many more of a 

 smaller size. Say that, on an average of sizes, they consumed 

 twenty a-piece, these for the five make one hundred. Each of the 

 parents consume say fifty ; so that the pair and family devour two 

 hundred every day. This, in three months, amounts to twenty 

 thousand in one season. But as the grub continues in that state 

 four seasons, this single pair, with their family alone, without reck- 

 oning their descendants after the first year, would destroy eighty 

 thousand grubs. Let us suppose that the half, namely forty thous- 

 and, are females, and it is known that they usually lay about two 

 hundred eggs each ; it will appear, that no less than eight millions 

 have been destroyed, or prevented from being hatched, by the la- 

 bors of a single family of jays. It is by reasoning in this way, that we 

 learn to know of what importance it is to attend to the economy 

 of nature, and to be cautious how we derange it by our short- 

 sighted and futile operations." Our own country abounds with 

 insect-eating beasts and birds, and without doubt the more than 

 abundant Melolonthae form a portion of their nourishment. 



In the year 1817, the Fabrician genus melolontha contained 

 three hundred and five known species, two hundred and twenty- 

 six of which still retained that name, and seventy-nine were sep- 

 arated into five distinct genera. A great number of new species 

 have since been added to this list, which it has become necessary 

 still further to subdivide. In a prize essay on the noxious insects 

 of this genus, written by me in 1826, and published in the tenth 

 volume of the Massachusetts Agricultural Repository and Journal, 

 several new genera were proposed, and the principal insects they 

 were designed to include were pointed out. Several years after- 

 wards it became known to me, that similar genera, founded on a 

 consideration of the same insects, had been made by European 

 naturalists, some of whom published the result of their investiga- 

 tions before, and others after mine had appeared. Those of my 

 names, therefore, that had been anticipated in point of time, must 

 be dropped ; the others, I have thought proper to retain in the 

 present essay. 



We have several Melolonthians whose injuries in the perfect 

 and grub state approach to those of the European cock-chafer. 



