326 NATURAL HISTORY. 



species. All are strictly coprophagous insects, exhibiting no special instincts, but breeding in the 

 substance which constitutes their food as adult insects. A remarkable exception to this uniform 

 habit lias, however, been discovered by Dr. Algernon Chapman, in the British species Aphodiiis 

 porcus, which he found to be parasitic on Geotrupes stercorarius. He states that at about the 

 time the parent Geotrupes closes the underground chamber in which she has laid one of her eggs 

 with a store of food for the larva when hatched, the female Aphodius forces a way into it, eats the 

 egg, which in volume is larger than herself, and having thus removed the prospective owner of the 

 store of pabulum, lays her own eggs in little cavities which she forms in the pabulum itself, thus 

 appropriating the supply of food for her own future offspring, and at the same time securing a snug 

 asylum, free from the perils of the above-ground abodes of her sister Aphodii. 



The genus Geotrupes forms the type of another sab-family of the section Geotrupinae, distin- 

 guished from the preceding by the small clypeus, which leaves the mandibles and other parts of the 

 mouth exposed. In habits the species are similar to those members of the Coprinae sub-family which 

 provide for their offspring by excavating tunnels or galleries under the droppings of large quadrupeds, 

 and laying their eggs in these secure retreats by the side of a store of provender. But from the 

 observations of Dr. Chapman we learn that the parent Geotrupes show much engineering skill in the 

 formation of these underground nesting-places. In watching Geotrupes stercortariua, he observed that 

 both male and female busied themselves in the work of carrying down pabulum into the burrows. 

 These latter consist first of a vertical shaft underneath a cow-dropping, and then of a subsidiary 

 gallery carried along the surface of the ground from this point to the edge of the dropping, where 

 the removed earth is ejected. In the walls of these a number of small horizontal cavities are 

 hollowed out at varying heights, each about an inch wide and four or five inches long, and in each a 

 siore of pabulum is placed and an egg deposited. The earth removed forms those little heaps of 

 mould always seen by the side of droppings where stercorarius is at work. The rounded further ends 

 of the cavities are firmly packed with concentric layers of dung, in the centre of which a kind of 

 cell is made, the Beetles apparently working with their fore tibiae as trowels in making smooth the 

 Avails, and on the floor of this the egg is laid. The remaining part of the tunnel is packed with dung, 

 layer by layer, before the work is completed. 



Six species of Geotrupes are found in Britain, including the G. typhous, remarkable for the 

 three horns projecting horizontally from the prothorax of the male. The genus is distributed over the 

 whole north temperate zone, some of the species from South Europe and Japan being of bright 

 coppery and golden colours. In Mexico and in Assam ai - e found rare forms, having long vertical 

 horns rising from the crown of the head. The allied genus Jlolbocerus, of more spherical shape, and 

 of pale reddish-brown colour, is most numerously represented in Australia, where the species exhibit 

 great variety and eccentricity of form in the horns of the males : one species (Jj. proboscideus) having 

 a long horizontal horn projecting from the head, slightly curving downwards, which simulates in 

 miniature the trunk of an Elephant. 



The sub-family Troginae resemble the Geotrupinae in the form of the head, but differ in the 

 simple structure of the fore legs, which are not adapted for burrowing. The species live, in fact, on 

 dried animal substances lying on the surface of the ground in sandy places, or on trees. Most of 

 them are oblong or oval insects of moderate size, with rows of tubercles along the wing-cases, coloured 

 like the sandy soil, and often coated with earthy material of the same colour. One group, however, 

 which are found only on trees, and have the remarkable faculty of retracting their limbs, and closing 

 themselves, like the Armadillo, into the form of little balls, are of polished metallic colours. 



The sub-families of the Pleurostictica legion are the MELOLONTHIX.E, or Cockchafers, the 

 RUTELIN.E, or Goldsmith-beetles, the DYNASTIX^E, or Elephant- and Rhinoceros-beetles, and the 

 CETONIIN^E, or Rosechafers. All are vegetable feeders in both their larva and their adult stages 

 the great majority in their larva state feeding on roots of herbage, the remainder, including most 

 of the Dynastinse and Cetoniina?, preferring decayed wood, some of the latter feeding on vegetable 

 detritus in the nests of Ants. In their adult stages they offer more variety of habits. The Melolon- 

 thinse are chiefly leaf-eaters ; many of the Rutelime prefer fruit, although foliage and flowers are 

 also resorted to ; some of the Dynastinte feed on succulent plants and the exudations of large forest 

 trees; whilst the Cetoniina? are pre-eminently Flower-beetles. 



