236 NATURAL ARRANGEMENT OF INSECTS. 



conceive a proximate affinity between such genera as 

 Acanthocerus and Trox. The former, like Agathidium, 

 has the faculty of rolling itself up into a complete ball, 

 indeed, so much so, that one we received from the 

 Brazils was transpierced through the elytra, near the 

 scutellum, and again through the head. It is other- 

 wise remarkable for the extremely dilated expansion of 

 its tibiae, which form thin plates, that fold up within 

 a cavity beneath the body ; and thus, when the insect is 

 rolled, there is not the slightest vestige of these limbs to 

 be seen for the tarsi fold back upon the tibiae. The penta- 

 merous tarsi, and lamellated structure of the apex of the 

 antennae, are all that seems to associate it here. If this 

 be admitted, we see no reason why one of the Bostri- 

 chidfs, the Phloeotribus Olece, which has likewise la- 

 mellated antennae, should not come into the iamellicorn 

 circle. The habits of Acanthocerus, also, are to frequent 

 flowers, and not carrion, or putrescent substances, like 

 all its present associates. Trox, to us, seems to have itself 

 a strong relation, perhaps of affinity if habits. and habit 

 can show this with Opatrum amongst Latreille's He" 

 teromera. Trox is of universal dissemination ; Acan- 

 thocerus is wholly American ; and it is difficult to say 

 what other insects should enter the group. [W. E. Sh.] 

 (210.) In the Aphodiince, we have greater uniformity 

 of general habit, as also of specific habits ; and this, 

 although a limited group in forms, is, especially in its 

 types, very abundant in species ; for Aphodius numbers 

 as many as any genus, except Onthophagus, within the 

 Iamellicorn circles : it is also found every where ex- 

 cepting in New Holland ; and the only departure from 

 the habits of the family is in JEgialia, a small genus, 

 consisting of but two species, one European and one 

 American, the European occurring in Great Britain, 

 upon our sandy coasts, where possibly it feeds upon 

 putrescent fish, or the rejectamenta of the sea. The 

 relative proportions of these five groups differ greatly 

 from the parallel series of thalerophagous Petalocera, 

 and would stand thus in round numbers. Scarabceina 



