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XXVIII. Descriptions of some new Species of Athyreus, a Genus of LameUi- 

 corn Beetles. By J. O, Westwood, Esq., F.L.S. 8fc. 



Read February 1st, 1848. 



1 HE genus Athyreus was first proposed by Mr. W. S. MacLeay, in the 

 appendix to the ' Horse Entomologicee,' for the reception of three Brazilian 

 species, A. bifurcatus, tridentatus and hidentatus, and was placed in the family 

 Geotrupidce, with the remark (p. 53), that " by way of proof that the Geotru- 

 pidcB are principally confined to temperate climates, I may observe that the 

 tropical insects of this family principally belong to the extreme genera, such 

 as Athyreus and Hyhosorus, the former of which approaches to the Scara- 

 bceidce and the latter to the Dynastidae ;" the relation of Athyreus to the 

 Scarahceidce being again alluded to in p. 123, in the observation, " Genus 

 admodum singulare, capite neglecto a Copride baud distinguendum, sed ab 

 Elephastomo quoque hand long^ distat." 



The characters of the genus as laid down by Mr. MacLeay do not however 

 give a clear idea of its peculiarities ; neither are the species, which he has too 

 briefly defined, to be identified with proper precision. The mandibles (Tab. 

 XXII. fig. a, a), for instance, instead of being flat on the upper surface are 

 quite concave, the lateral and apical portions not being covered by the labrum; 

 and as each is of a different shape, a single description will not apply to 

 them. I have given a delineation of them in the accompanying figures, and 

 must here only allude to the black, horny, flattened molar plate at the base 

 on the inside, which is destitute of those curious transverse ridges which are 

 seen in the Melolonthidce ; this peculiarity being an important one, bearing 

 directly upon the nature of the food of the insects, which is ground by these 

 two hard parts of the mandibles being brought together by the action of the 

 strong muscles inserted near the outer base of the jaws, close to the deep 

 notch which will be seen near the small ball that fits into the socket of the 

 head where they are attached. 



