IQ4 AN INTRODUCTION TO ENTOMOLOGY. 



B. Second segment of antennae longer than either the third or fourth. 



METROBATES. 

 BB. Second segment of antennas shorter than either the third or fourth. 



STEPHANIA. 



AA. Body elongate, more than four times as long as broad ; pronotum much 

 longer than broad. 



B. Antennae longer than head and pronotum together; the posterior tibiae 

 and tarsi together much longer than the intermediate tibiae. 



LIMNOPORUS. 



BB. Antennae shorter than the head and pronotum together; the posterior 

 tibiae and tarsi together but little longer than the intermediate tibiae. 

 C. First segment of antennae nearly equal in length to the fourth. 



LlMNOTRECHUS. 



CC. First segment of the antennae considerably longer than the fourth. 



HYGROTRECHUS. 



Closely allied to Stephdnia, and resembling it in the form of their 

 bodies, are the species which constitute the genus 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). 



Family XX. LiMNOBATiD^:.* 



The members of this family are very long, slender insects, with 

 linear legs and antennae. The head is nearly 

 cylindrical, and longer than the thorax ; the eyes 

 are round, projecting, and placed a little nearer 

 the base than the tip of the head. These insects 

 creep slowly upon the surface of the water ; they 

 carry the body considerably elevated ; and are 

 found mostly where plants are growing in quiet 

 waters. "They delight to remain at rest, with 

 perhaps a single claw hooked to some projecting 

 object. When disturbed, they move very slowly, 

 and seem disposed to save themselves rather by 

 concealment among rubbish or tangled growths 

 than by active movements. The young forms 



FIG. \t>$.Limnobates 111 



Uneata. are so very slender that they can only be detected 



with great difficulty in the places to which they resort." (Uhler.) 



* Limnobatidae, Limnobates: limne (Xijuvij), a salt marsh; dates (ftdrrj^), one that 

 treads. 



