ADOREIUS. 297 



ridge is not easily visible, it may be readily made so by slightly 

 raising at its extremity the elytron through which the specimen 

 is not pinned. This peculiar structure, which is found in all 

 those species just mentioned as having smooth opaque epipleurae 

 to the elytra, as well as in certain others, is evidently of some 

 importance in relation to the habits of the species. Obviously it 

 may be useful for insects which habitually conceal themselves 

 underground to possess a special means of excluding earthy par- 

 ticles from the cavity containing the wings and most of the 

 spiracles, but we do not at present know of any particular in 

 which those Adoreti not possessing this feature differ in habits 

 from those possessing it. 



The front tibia bears three external teeth and is sometimes 

 finely serrated above them. The tarsi are generally moderately 

 slender, but the hind ones may be short and compact. The claws 

 are very unequal, the inner front and outer middle and hind ones 

 very long, and the first and second cleft at the tip. In the male 

 the cleft is generally very minute, at a little distance from the 

 apex, and sometimes not very easily seen. In Adoretus minutus, 

 Brenske, the longer claw of all the feet is cleft, and in the four 

 anterior feet the cleft is very conspicuous and the inner branch 

 of the claw rather dilated. In A. nasaUs, Arrow, and species 

 allied to it, the claws are not cleft. 



In the male Adoretus the pygidium is moderately large and 

 exposed, and the abdomen is flat or a little hollowed beneath. 

 In the female the pygidium is much shorter, while the last ventral 

 segment is correspondingly large, and the terminal part of the 

 abdomen is very convex beneath. The eyes are generally larger 

 in the male than in the female and the clypeus smaller, and in 

 some species (as in A. versutus, Har.) the difference so produced 

 between the two sexes is very marked. 



Certain of the Indian species included here in the genus 

 Adoretus have been separated by Reitter and Ohaus under the 

 names Lepadoretus, Chcetadoretus and Prionadoretus. Lepadoretus 

 is distinguished only by the clothing consisting of scales instead 

 of hairs or setae, and Chcetadoretus by the occurrence of a few- 

 longer erect hairs placed singly amongst those on the elvtra. 

 The difference between hairs and scales is quite indefinite, and 

 the scattered erect setae make their appearance by such imper- 

 ceptible degrees that they seem to me equally unsuited to provide 

 a line of demarcation. Prionadoretus is characterised by the 

 edges of the produced labrum being deeply, instead of slightly, 

 indented ; but this again is found in different degrees of develop- 

 ment, and Ohaus has not mentioned that one of the commonest 

 Indian Adoreti, A. Umbatus, Bl., has the labrum of the Prion- 

 adoretus type. A more important feature of that species in my 

 opinion is the reduction in the number of joints to the antenna. 

 Another new species, A. nasalis, closely related to the typical 

 Prionadoretus, has all the claws simple and the labrum bears a 

 very peculiar crest, unlike anything known elsewhere. For the 



