BEETLES. 



369 



The genus Dynastes includes, in another group of beetles, even larger species 

 than are those of Goliathus among the cetonians. In Dynastes the tarsal claws are 

 equal and the anterior tarsi elongated, the anterior coxa? transverse and not prominent, 

 the prnthorax and head armed with horns or tuhercles. I), tityus is one of the largest, 

 possibly the largest, species of Coleoptera found in the United States, and occurs in the 

 southern part of the country as far north as Philadelphia. It is al)out two inches long 

 and one inch wide; is of a general greenish-wliite colur, with black legs and brownish 

 black spots upon the elytra. In the males the anterior portion of the prothorax is 

 provided with a downward-curved black horn that approaches at its tip a similar 

 upward curved horn from the head. The larva3 of this and other species of Dynastes 



Fig. 428. — Mtgasoma elephas. 



live in decaying wood. Dynastes hercides, from tro])ieal America, I'cachcs a length 

 of six inches, of which the curved prothoracic horn makes nearly one-half. The 

 elytra are light olive green, spotted with black; the rest of the beetle is shining black. 

 The prothoracic horn is lined with yellow hairs beneath ; and below it, as in D. tityus, 

 is a shorter upturned horn from the head. The articulation between the prothorax and 

 head allows these horns to be separated and brought toward each other like the two 

 halves of a j)air of forceps. D. neptumts, a species of about the same size as is D.her- 

 cnles, also inhabits tropical America. Closely allied to Dynastes, bnt sejiarated from 

 it by its glabrous prosternal jirocess, is Mcgasonia. M. elephas, M. typhon, and 31. 

 eictceon are all large species from Ccntial and South America. M. thersites is a Cali- 

 fornian species. 

 VOL. II. — 24 



