516 AN INTRODUCTION TO ENTOMOLOGY 



these insects is the lamellate form of the club of the antennas, the 

 segments constituting it being greatly flattened, and capable of being 

 brought close together. It is this character that suggests the name 

 lamellicorn beetles. In the next family, the Trogidee, which has 

 recently been separated from this family, the antenna are lamellate. 

 The two families can be separated by the fact that in the Scarabasidae 

 the epimera of the mesothorax extend to the coxae, while in the 

 Trogidas they do not. 



According to their habits, the members of this family can be 

 separated into two well-marked groups — the scavengers and the leaf- 

 chafers. 



THE LAMELLICORN SCAVENGERS 



The lamellicorn scavengers in both the larval and adult states feed 

 upon decaying vegetable matter. Nearly all the species live in dung, 

 chiefly that of horses and cows ; but a few species feed upon fungi. 

 The following are the more common representatives of this division. 



I. The tumble-bugs. — These are the most familiar of all dung- 

 beetles, for their peculiar habits have attracted much attention from 

 the earliest times. They are of rounded form, and the wing-covers 

 are shortened so as to expose the tip of the abdomen. They are 

 generally black, but some are colored with rich metallic hues. They 

 vary greatly in size. 



The name tumble-bus: refers to the habit which many species 

 exhibit of forming round balls of dung, which they roll long distances 

 and then bury. They often work in pairs and it was formerly be- 

 lieved that such a pair was a male and a female working together to 

 make provision for their progeny ; but Fabre found by dissecting the 

 beetles that the two members of a pair often proved to belong to the 

 same sex; and concluded that the eager fellow-worker, under the 

 deceitful pretense of lending a helping hand, niu-ses the scheme of 

 purloining the ball at the first opportunity. 



According to the observations of Fabre ('79 and '11), the balls 

 made early in the year are devoured by the beetles, which bury them- 

 selves with them and feed upon them. Later other balls are made and 

 buried, upon each of which an egg is laid. The larva hatching from 

 this egg feeds upon the ball of dung, and when full-grown transforms 

 within the cavity in which the ball was placed. 



This strange habit of rolling these balls has occasioned much 

 speculation as to its object, and has been the source of many super- 

 stitions, especially in ancient times. The only reasonable theory that 

 we have met is that, as many predacious insects frequent the masses 

 of dung from which the balls are obtained, in order to prey upon the 

 larvae which live there, the more intelligent tumble-bugs remove the 

 food for their larvae to a safe distance. 



The most noted member of this group of genera is the sacred 

 beetle of the Egyptians, Ateuchus sdcer. This insect was held in 



