78 ON THE GLAPHYRID^ OF NEW HOLLAND, 



Geuera, return into themselves ; that is, that the sei-ies of natural 

 affinities will, if followed, invariably lead back to the point started 

 from, which fact may be represented by a circle, ellipse, or any curve 

 that returns into itself. He has also, in the same work, shown 

 that in general the number of groups, into which such a natural 

 group as above described, may be subdivided, is five. 



The applicability of this theory to the present family is 

 remarkable. I observe, moreover, that the five typical groups, 

 whether called families or genera, have each a geographical as 

 well as a structural character. 



Thus starting from Anisonyx as the type of the South African 

 group, which, through the European genus Hoplia, connects the 

 GlaphyridcB with the Melolonthidce, we pass to Phyllotocus as 

 representing the Australian group, at which point I believe the 

 connexion of the family with the Getoniidce will be found to 

 occur, probably by the genera Cheiragra and Valgus ; thence by 

 the genus, to which I have given the name Macrothojos, to the 

 South American group, of which we may take the genus 

 Gratoscelis as the type ; thence to the North American genus 

 Tjichnanihe ; thence to the Mediterranean group, of v/h:c!i Gla- 

 phyrus or Amphicoma may be taken as the type, from which 

 the passage to Anisonyx is easy, thus completing the circle. 



I mentioned at the commencement of this paper that the 

 insects grouped together under Fischer's genus Phyllotocus differ 

 considerably in important parts of then* external anatomy; indeed, 

 we find in species of this genus, variations in the form of the 

 maxillae, mentum and palpi, which, in most families of the 

 Coleoptera would mark very distinct genera. 



To avoid, howevei', unnecessary subdivision, I intend to 

 retain in the genus Phyllotocus all the species of the Australian 

 Glaphyridce which have the epistome double, subdividing them 

 as follows : 1st, those with bodies more or less smooth, palpi 

 long, and maxilloe with the outer lobe membranaceous, trigonal 

 and ciliated, the inner lobe being dentiform. 2nd, those with 

 bodies more or less hairy, palpi not long, and maxillfe for the 

 most part consisting only of pencils of hair with scarcely a rudi- 

 ment of either lobe. P. MacLeayi of Fischer is the type of the 

 first subdivision, and P. rufipennis may be taken as the type of 

 the second. 



