COLEOPTERA. DYNASTIDiE. 211 



robust and horny {fiy. 21. 3.), furnislied with one or two obtuse 

 teeth ; the maxillae are either terminated by a coriaceous ciliated lobe, 

 or by an elongated corneous piece, having one or several acute teeth 

 on its inside (^firj- 21. 4.) ; the mentum {^fig- 21 . 5.) is large, concealing 

 the labium, and of an ovoid or triangular form, truncated in front ; 

 the prosternum is not produced behind into a lobe; the tarsal claws 

 are of equal size, and the scutellum is distinct ; the elytra do not 

 entirely cover the extremity of the abdomen ; the antenna? are 

 10-jointed (j^^. 21. 6.) with the club 3-jointed ; the central lamella 

 not being enclosed within the two external ones. 



The colours of these insects are generally of a dark rich brown or 

 chesnut colour. 



Latreille has divided this family into two groups, from the unarmed 

 or toothed structure of the maxillae ; but the dissection of a very ^e.^ 

 species of Oryctes and Dynastes will convince any one that the two 

 groups are so gradually blended together that other characters must 

 be resorted to. 



The Dynastidte reside either in rich vegetable mouldy or in the 

 putrid detritus resulting from the decomposition of trees. According 

 to Humboldt, however, Geotrupes i^^geon is found in Chili upon 

 cowdung. 



The common continental species, Oryctes nasicornis, a reputed 

 native of this country, is found in the larva state [jig' 19. 4.) in tanpits ; 

 and De Geer mentions that, in shifting a dung heap at Stockholm, 

 which had long remained in the same spot, he dug out a vast number 

 of the larvae of this insect, as well as specimens of the imago. The eggs 

 are oblong, about the size of a grain of hemp-seed, and of a yellow 

 colour ; the larva continues in that state four or five years, and then 

 encloses itself in an oval arid very smooth cocoon ; the pupa lies upon 

 its back, and the imago remains in its cell a month after it has attained 

 the perfect state. 



Mr. MacLeay has made various interesting observations upon the 

 structure of some of these, insects, with a view to the discovery of 

 their various habits. M. Lacordaire, however, who has carefully 

 described the habits of the Coleoptera of Guiana, states that they are 

 much alike in this respect, concealing themselves during the day in 

 holes dug in the earth, or in the decomposed trunks of trees, or 

 running about the footpaths in woods; on the approach of night 

 they leave their retreats and fly around the trees to a considerable 



p 2 



