ON DECOMPOSED VEGETABLE MATTER. 6? 



have been entirely changed into a rich mould, he one day 

 dug out a prodigious quantity of the larvae of Oryctes nasi- 

 cornis, accompanied by specimens of the perfect insect. 

 We see therefore that the unarmed maxillte suit very well 

 with the. consistence of the substance which this species 

 has chosen for its food. But do all the Dynastida live in 

 the same manner ? This is a question that in the present 

 state of the science cannot be answered. It is possible that 

 those which are provided with teeth to their maxillas have 

 to act on harder materials than the rich mould or soft tan 

 on which the Orj/c/es lives. It may be that the genus JXy- 

 nasfes is truly lignivorous, or at least feeds on wood and 

 other vegetable matter when in a less decomposed state 

 than seems suitable for the insects with unarmed maxillae. 

 But these are points yet to be determined ; and certainly 

 are more interesting, more worthy of examination, and 

 more likely to advance the cause of the science, than the 

 simple discrimination of species and synonyms. 



The Dynasiidce, though a numerous family, are by no 

 means equably dispersed over the globe; Europe contain- 

 ing only three or four species, whereas on the other hand 

 the torrid zone is pestered with these insects, formidable 

 however rather from their size than from any noxious 

 qualities. I have calculated the proportion of species 

 from countries within the tropics to be to those from 

 without about 8:1. and there is reason to believe that 

 this estimate comes very near the truth. 



Some insects of this family approach excessively close 

 to the thalerophagous circle, as will be seen by the 

 anatomical details in the Appendix. In fact, it is no easy 

 matter to distinguish the Dynastida from some of the 

 AnoplognathidcE and RutelidfB : but the best distincti\ e 



F 2 



