508 ANALYSIS. 



mediate legs touch each other at their base ; yet Latreilie 

 (Hist. Nat. des Crust, et des Ins. X. p. 92.) gives the follow- 

 ing character to his genus Ateuchus, as distinguishing it from 

 Aphodius, " Pattes inter mediaires plus ecarttes entre elles 

 a la naissance que les autres." If, however, this character 

 be held only as the structure to which the Scarabaidoi 

 have a general tendency, it is without doubt perfectly cor- 

 rect ; and in this sense alone it has been adopted in the 

 general description of the family given in the preceding 

 Essay. Another proof of the futility of absolute rules of 

 division in natural history is, that in the work above quoted, 

 Latreilie separates Ateuchus^om. Onicis by the latter having 

 no anterior tarsi. We perceive, however, that these organs 

 are equally deficient in Heliocantharus, Mnematium and 

 Pachysoma, which all formed part of his genus Ateuchus. 

 In a letter recently received from Mr. Kirby, he 

 states to me that he has perceived in Pachysoma an 

 approximation towards the Gymnopleuri of lUiger. In 

 this opinion I perfectly coincide with him, on account of 

 the globular form of the clava of their antennae among other 

 considerations. But then the hiatus between them is so 

 great, that it becomes absolutely necessary to suppose the 

 existence of an intermediate type. 



TYPUSIV. Nondumdetectus. 



From theory, the clava of the antennas of this type ought 

 to be globose, aud the clypeus bidentate. The remark- 

 able propensity which the other four types of ScarabcEus 

 have to make Africa their habitation, renders it probable 

 that this unknown type still exists in the interior of that 

 vast peninsula. Mr. Ritchie's late discovery of the second 

 type of the genus fully warrants the supposition. It is at 



