264 NATURAL HISTORY OF ARTHROPODS. 



throughout the Atlantic States. The genus is exclusively American, and several 

 nominal species have been made upon characters which seem too evanescent for sub- 

 stantial separation. But since we now know them to vary here in harmony with the 

 soil upon which they live, as well as with reference to their condition of vigor and 

 maturity, we may safely infer that similar modifications will affect them and change 

 their colors and markings in the other countries where they dwell. 



Next akin to Gnlgulus is the old genus Mononyx, whicli Dr. Stal has erected into 

 a sub-family, embracing five so-called genera. The genus Mononyx, as now restricted, 

 comprehends most of the American forms, and a single species from New Guinea, 

 which has a wider thorax than is normal to the grouj). These insects are all rough 

 and uneven on the upper surface, almost cut square off iu front, bluntly rounded, 

 behind, almost flat, of a mud brown or blackish color, and fore-legs fitted, as in the 

 j)rcceding genua, for seizing and holding insect prey. 



One species inhabits the United States, being found in Georgia, Florida, and 

 Texas, the M. stygicus. It is a most unattractive species, dark brown, or pale brown, 

 obscured by darker on the discs of the prothorax and wing-covers, hispid and tuber- 

 culated upon the uneven prothorax, with its sides and the base of the costal area of 

 the corium flattened, expanded, and thin. The legs are dull yellowish, darker on the 

 shanks and tarsi, and with piceous spines and nails. The anterior femora are very 

 short, broad, and flat, triangularly produced below, and on the lower side closely 

 armed with short, fine teeth ; the two posterior pairs of femora are crossed by two 

 pale brown bands, and the knees are also obscured. A less prominent dilatation of 

 the front angle of the prothorax than in Galgulus is here scooped out to cover the 

 antennse in conjunction with the excavated base of the eyes, but in this it does not 

 seem to form such a close cover beneath. The vertex slopes forwards, and is termi- 

 nated on a ridge by two short processes placed upon the middle, the front is thus 

 carried beneath and the rostrum is bent back against the sternum, as in some Homop- 

 tera. Here the eyes are not nearly so prominent as in the preceding genus, the head 

 is much narrower, and the ocelli are disguised by the inequalities and roughness of 

 the surface. 



This species is one of the smaller members of the group, and commonly measures 

 a little more than one-fourth of an inch in length, by two full lines in width. Very 

 little has been reported respecting the habits of these insects ; we only know that 

 they frequent damp ground near water, and that they seize their prey by using the 

 raptorial fore-legs, which constitute a lever by the movement of the shank against the 

 knife-like, armed expansion of the femur. The nail which constitutes the end of 

 the fore-tarsal joint is shai'p and curved. 



Probably the most monstrous form of the group is the large and broad M. ampli- 

 collis, which inhabits eastern Peru and the region watered by the Orinoco River. It 

 is of a dull mud-brown, with the great broad prothorax spread out sideways like wings. 

 Its head, prothorax, and scutellum are humped, ridged, uneven, and roughly punctate, 

 and the head strongly suggests that of a cicada, both in form and direction. Its fore- 

 legs are correspondingly thick and powerful, and strongly sugg«sts the energy which 

 it might employ in conquering its victims. 



All of the foregoing are fully winged, with complete and ample membrane, which 

 widely overlaps the tip. 



Various other, in general more simply constructed, species inhabit Mexico, Central 

 America, and the tropics of South America ; all are inhabitants of warm regions, and 



