372 AN INTRODUCTION TO ENTOMOLOGY 



Trepobates. — This genus is represented only by T. pictus. This 

 is a beautiful vellow and black species, which is quite widely distribut- 

 ed. 



Rheumatobates.— Three species of this genus have been described. 

 The males are remarkable for the strange form of the posterior femora, 

 which are strongly bent, and the shape of the antennae, which are 

 fitted for clasping. 



Halobates. — These are truly pelagic insects, living on the surface 

 of the ocean, often hundreds of miles from land. They are most 

 abundant in the region of calms near the equator; they feed on the 

 juices of dead animals floating on the surface, and probably attach 

 their eggs to floating sea-weed (Sargassum). H. micans is found off 

 the coast of Florida and H. senceus off the coast of California. 



Family MESOVELIID^ 



The Mesoveliids 



This is a small family of which only two species have been found 

 in North America. These are the following . 



Mesovelia mulsdnti. — This is a small bug, measuring only 4 or 

 5 mm. in length; it is of a pale yellow color marked with brown. 

 The antennae are long, filiform, and four-jointed; the beak is three- 

 jointed; the legs are moderately long and slender; and the tarsi are 

 three-jointed. This species is dimorphic, the adults being either winged 

 or wingless. In the winged form, the membrane of the hemelytra is 

 without veins. 



This species lives on the surface of quiet waters and on rafts of 

 floating vegetation and is predacious. It is furnished with an ovi- 

 positor and embeds its eggs in the stems of aquatic plants. 



Mesovelia douglasensis. — This is a smaller species than the pre- 

 ceding; the length of the female is 2.1 mm., of the male 1.8 mm. It 

 is olive-brown in color. It was recently discovered and described by 

 Professor Hungerford ('24). It was found near Douglas Lake, Michi- 



Family HEBRIDiE 



The Hebrids 



This family includes very small plump-bodied bugs, measuring 

 less than 3 mm. in length. The 

 antennas are either four-jointed or five- 

 jointed; the beak is three-jointed; and the 

 tarsi are two-jointed. Ocelli are present. 

 The head and thorax are sulcate beneath. 

 The clavus of the hemelytra is similar in 

 texture to the membrane, which is without 

 ^'uehru's ^^"'''^^'^'■°'' °^ veins (Fig. 427). Two genera of this family 

 are found in the United States. 



