DYNASTIN.E 259 



Body much smaller, the anterior legs not distinctly modified sexually; 

 cephalic horn of the male without trace of a basal dorsal process, the 

 prothorax with a short anteriorly projecting central process, which 

 is briefly bifurcate; pronotum without a basal bead in the female, 

 except very near the lateral angles and with only a feebly defined 

 beading in the male. [Type Megasoma thersites Lee.] . . Megasominus 



I am unable to say whether the moderately large Brazilian 

 Scarab<zus hector of Gory might enter the genus Megasominus or 

 not, the probabilities being however against it, because of the 

 w r idely distant and wholly disconnected habitats. The genus 

 Megasoma Kirby, as at present constituted, is rather composite 

 and several genera are included under that name, though in some 

 cases not separable by any very radical differential characters; 

 perhaps general habitus is among these one of the more important. 



Dynastes Kirby. 



The maxillary galea in hercules is said by Burmeister to have 

 several small denticles, but so far as observable in my specimens, 

 without dissection, it seems to be simple and acutely pointed at 

 apex in that species; the thoracic horn of the male is often very 

 long, fully as long or longer than the entire body, and the lateral 

 thoracic spines are placed on its sides at or near basal third of its; 

 length. In the Mexican hyllus Chev., and our common tityus, 

 however, the horn is very much shorter and the spines are on the 

 pronotal surface very near its base. The pygidium in the male is 

 sometimes so retracted in plane as to appear as one of the ventral 

 segments when viewed from beneath. We have two species and 

 one apparent subspecies as follows: 



Thoracic process very short, never distinctly longer and often much 

 shorter than the length of the prothorax, attenuate toward the apex, 

 which is angularly notched but not expanded or otherwise modified. 

 Body very stout, oblong-oval, very convex, shining, the male pale 

 greenish-gray above, mottled on the elytra with spots of blackish- 

 piceous, smaller or larger in size and often confluent, sometimes 

 having a somewhat confusedly serial arrangement, the head, medio- 

 apical part of the prothorax and thoracic processes black; under 

 surface very dark castaneous throughout; head three-sevenths as 

 wide as the prothorax, punctulate, the clypeus trapezoidal, with 

 moderately narrow, unreflexed and sinuato-truncate apex and 

 rounded angles, its surface in great part occupied by the base of the 

 erect and somewhat posteriorly arcuate, acutely pointed horn, 

 which is scarcely one-half longer than the head and almost exactly 



