256 NATURAL HISTORY OF ARTHROPODS. 



bounded by raised lines before and on the sides, and also has a carinate line 

 running down the middle. The under side is also more or less spotted and marked 

 with fuscous, while all the femora and tibiae are more or less distinctly thrice-banded 

 with the same color. On the inner margins of the preceding, including the tarsi, as 

 also the nails, a distinct blackish color prevails. The largest specimen that has 

 yet been brought to this country measures four inches to the tip of the abdomen ; but 

 this is quite exceptional, since we rarely meet with individuals which exceed three and 

 a half inches in length. This large one also measures nearly one inch and a quarter 

 across the base of the prothorax. It is a formidable monster in the pools of Demerara, 

 where it lurks on the bottom of the muddy pools which match its color, ever ready to 

 grasp the unwary fish in the cruel embrace of its sharp hooked fore-legs, there to remain 

 fixed until life becomes extinct with the outflow of its blood. 



Scarcely less rapacious are the species inhabiting the United States. One of these, 

 B. grisea, is the facile master of the ponds and estuaries of the tidal creeks and rivers 

 of the Atlantic States. Developing in the quiet pools, secreting itself beneath stones 

 or rubbish, it watches the approach of a fomotis, mud-minnow, frog, or other small- 

 sized tenant of the water, when it darts with sudden rapidity upon its unprepared victim, 

 grasps the creature with its strong, clasping fore-legs, plunges its deadly beak deep into 

 the flesh, and proceeds with the utmost coolness to leisurely suck its blood. A copious 

 supply of saliva is poured into the wound, and no doubt aids in producing the paralysis 

 which so speedily follows its puncture in small creatures. It is of a dull grayish brown, 

 varied with fuscous, and more distinctly marked with a blackish patch each side of the 

 prothorax, and on the sides of scutellum, and striped on the breast with three broad 

 lines of the same color, which widen behind and become less distinct upon the venter. 

 In this species the pectus and postpectus are yellow, and thus the black stripes are 

 there brought out with greater distinctness. The legs are broad, 'and the femora and 

 tibiae are sometimes indistinctly thrice-banded with blackish. Usually the upper 

 surface is smoother than in the other species which this most resembles. Its anterior 

 legs are also longer, and instead of having the longitudinal groove on the front side of 

 the femora, the surface is rounded off and more widely clothed than usual with stiff, 

 short, velvety pile. A new sub-genus, Benacus, has been designated for this form by 

 Dr. Stal, based upon the absence of the femoral groove, and presence of the velvety 

 turned edge. It is much narrower anteriorly than the other species, -B. americanum, 

 which also inhabits the Atlantic region, and to which it bears some resemblance. The 

 latter, however, has shorter and wider fore-legs, besides the femoral groove; and 

 it lives in quiet, fresh, or brackish waters, having essentially the same habits as the 

 preceding. Both of these insects have the usual caudal setae, which are retractile, 

 and are often concealed by being drawn within the last segment of the abdomen. The 

 former is distributed from Lower Canada as far as the West India islands, while the 

 latter ranges from Oregon and Washington Territory across the continent, and from 

 thence south into Texas and Mexico. 



B. indica is a pale yellowish species which inhabits China and India, It sometimes 

 measures three and a quarter inches in length, and it has often been confused with the 

 South American species first mentioned, to which it bears some resemblance. B. colos- 

 sicum, from Cuba and Central America, is the darkest and heaviest built of the large 

 species. It is very coarsely wrinkled and granulated upon the thorax and scutellum, 

 and has a deep, bent, depressed line crossing the prothorax and bending towards the 

 shoulders on each side. Its fore-femora are covered all over with very short, close-set 



