ANALYSIS. 493 



solitary example of generic regularity in the distribution 

 of nature, and that in both Phanaus and Scarabaits the 

 theoretical genus of Linnaeus appears to be exemplified, 

 will be attempted in the present and concluding chapter, 

 of which the leading object is to ascertain the place of 

 Scarabceus Sacer in the smallest group to which it can be 

 referred. 



With respect to the Saprophagous Petalocera, but par- 

 ticularly to the three Coprophagous families, it may be 

 said that they walk not on their tarsi, but on the extremi- 

 ties of their tibiae. We may observe this so well in Geo- 

 trupes stercorarius, that, excepting in certain .cases where 

 the insect hangs by the ungues of the tarsi, we are utterly 

 unable to imagine the use of them. In the genus Phanaus, 

 where the ungues themselves are deficient, it is particularly 

 difficult to determine the use of the tarsi, although it is 

 very easy to conceive them to be a great inconvenience to 

 the animal. Indeed, on this very account the tarsi in Co- 

 prophagous insects become often obsolete, and their use 

 as organs of prehension is in some measure supplied by 

 one or two calcaria fixed at the extremity of the tibiae. It 

 is on these that, accurately speaking, the animal walks. 

 After the discovery of the principle upon which the natural 

 group of Phanans was constructed, I turned my attention 

 to the true Scarabcei, in the hope of being able to apply a 

 similar plan to these more celebrated insects. But every 

 attempt failed, because, although my series of affinity was 

 to a certain degree very distinct, I had no point about 

 which my group could centre. It was in this state of doubt 

 that I received a letter from the Rev. Mr. Kirby, to whose 

 discoveries I have so often already alluded, announcing a 

 new principle of arrangement, founded on the compara- 



