BEETLES. 



373 



FIG. 433. GeotrujH's 



tl/pll<KUS. 



segments, the posterior pair of stigmata being covered by the elytra. The antennae 

 have from nine to eleven joints, of which the outer three only, in all genera except 

 Pleoeonia, form a compact club. The species of this sub-family mostly live in excre- 

 ment, a few in other decomposing matter. 



The species of Tro.v. have five ventral segments visible, and the epimera of the 

 mesothorax do not reach the rounded coxa 1 . The numerous 

 North American species of this. genus are oval beetles, mostly 

 with rough surface. They feed upon dried decomposing animal 

 matter, and many species are found about the refuse of tanneries, 

 and upon the hoofs and hair of decaying animals. 



The species of Geotrupes have the antemue eleven-jointed 

 with lamellate club, the mandibles well developed, and the ab- 

 domen exposing six ventral segments to view. Most of the 

 species are black, some with a bluish or greenish tinge ; a few 

 species have brilliant metallic coloration. The elytra are usually 

 striate, the prothorax sometimes armed with horns or tubercles, as in G. typhoeus, a 

 species common in Europe. The larvae of Geo(rtipes develop in masses of excrement 

 which the parents bury in the ground, and in each of which the female deposits an 

 egg. Seven species of this genus have been described from North America. Several 

 of them are quite common, and can be found by digging in the earth about cow-dung 

 during late summer and autumn. 



The large genus Aphodlxs numbers over fifty described species in North America. 

 Their antennae are nine-jointed, the posterior tibiae have two spurs, the front tibiae are 

 strongly toothed on the outer margin, the epimera of the metathorax are not visible, 



and the elytra are striate. The species of this genus are 

 mostly of small size, A. fossor being one of the largest 

 species. Their larvae feed in excrement and develop rapidly. 

 Heeger found that the larvae of A. fvntens, a common Euro- 

 pean species, hatched from the egg in from ten to twenty 

 d;iys; the larvae moulted three times, attaining full growth 

 in from four to five weeks ; and pupation lasted from four- 

 teen to twenty days. Chapman observed that A. porcits, 



another European species, destroys the eggs of Geotrupes stercorarius, and uses the 

 passages of the latter insect for its own oviposit ion. Species of ApJtodius have been 

 found near the crater of Vesuvius, where the sandy lava had a temperature of 182 F. 



Six of the species of Aphodius that are found in the United States were introduced 

 from Europe. Among these A. fossor is large and entirely black; A. firnetarius is 

 about 0.3 of an inch long, and black with red elytra; and A. inqmnatns is about 0.2 

 of an inch long, black, with portions of the elytra yellowish. 



Among the dung-beetles of robust form and moderate or small size, the genus 

 Onthophagus includes a large number, of which but a few are found in North America. 

 They have nine-jointed antennae and no scutellum, the third joint of the labial palpi 

 is obsolete, and the distal end of the middle and of the posterior tibiae is dilated. One 

 of the commonest kinds in the eastern United States is 0. latebrosus, a brownish black 

 species about 0.25 of an inch long and nearly 0.20 of an inch wide. From the posterior 

 end of the prothorax to the front of the head is over one-half the total length of this 

 insect. In the males a broad, almost bi-lobed, horn extends out from the fore part of 

 the prothorax and shelters the head. 



Fin. -lot. Avhodius /o.s'.sw and 

 larva. 



