ON DECOMPOSED VEGETABLE MATTER. 65 



sccpiuspubescens, coleoptris abdomen postice non ob- 

 tegentibus. Thorax scepe cornutus, vel mucronatas 

 vel excavatus. Scutellum distinctum, triangidare. 

 Sternum nanquam productum. Pedes validi, tar- 

 sorum unsiiibus indivisis. 



o 



Observations. 



This family is remarkable as well for containing some 

 of the most bulky of coleopterous insects, as for the dif- 

 ference which often occurs in the external appearance of 

 the sexes. It may be separated fi'om the TrogidcE. and 

 Geotrupidcz with ease on examining the labrum, which 

 in the Dyiiastidce is almost always concealed under the 

 clypeus, instead of being distinct as in the other two cases. 

 1 have here, as also in the corresponding family of the 

 circle of Thalerophagous Petalocera, in some manner 

 disregarded the shape of the maxillie for the sake of 

 general habit. Latreille in his various works has made a 

 distinct division of the Dynastida which have their max- 

 illas unarmed. But the general habits and appearance of 

 the genera Oryctes and Dynastes being so very similar, 

 and several insects occurring to fill up the chasm between 

 them, I conceived that it would be an artificial interrup- 

 tion of the order of Nature, to place two such insects as 

 Oryctes nasicornis, lUig. and Scarabeus Boas, Lat. in 

 different families. 



The DyiiastidcB live either in rich vegetable mould or in 

 the putrid detritus which results from the decomposition 

 6f trees. Perhaps also some are strictly lignivorous, par- 

 ticularly the large foreign species, of Dynastes; but the 

 truth is, that the economy of these insects has hitherto been 

 so httle studied, that it is almost entirely from analogy that 



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