CLASSIFICATION OF INSECTS 309 



R. Hind tarsus without claws. 



F, Pronotum overlapping head above. Back-swimmers. 



(Page 1 08) NOTONECTIDAE 



FF. Head overlapping prothorax above. Water-boatman. 



(Page 1 08) CORISIDAE 



EE. Hind tarsus with claws. 



F. Caudal end of abdomen furnished with a respiratory 

 tube. Water-scorpions. (Page 109) . . . NEPIDAE 

 FF. Caudal end of abdomen without respiratory tube. 



G. Hind legs flattened, adapted for swimming. Giant 

 water-bug. (Page 109) . . . BELOSTOMATIDAE 

 GG. Hind legs slender, not adapted for swimming. 



NAUCORIDAE 

 CC. Antennae at least as long as head. 



D. Head as long as entire thorax LIMNOBATIDAE 



DD. Head shorter than thorax. 



E. Last segment of tarsus more or less split, with claws 



inserted before apex. 

 F. Body elongated ; beak four-jointed. Water-striders. 



(Page 109) HYDROBATIDAE 



FF. Body usually stout and oval ; beak three-jointed. 



VELIDAE 

 EE. Last segment of tarsus entire, and with claws inserted at 



apex. 



F. Antennae of three or four segments. 

 G. Beak three-jointed. 



H. Body very long and slender . . EMESIDAE 

 HH. Body not long and slender. 



/. Front legs with greatly thickened femora. 



Ambush-bugs. (Page 114) . PHVMATIDAE 



//. Front legs with normal femora, or at least not 



unusually wide. 

 J. Antennae of three segments. Assassin-bugs. 



(Page 112) REDUVIIDAE 



JJ. Antennas of four segments. 



K. Tarsus of two segments ; body very 

 flat. Flat-bugs .... ARADIDAE 

 KK. Tarsus of three segments. 



L. Dorsal portion of body more or less 

 rounded ; beak long, reaching to or 

 beyond second coxa. Shore-bugs. 



SALDIDAE 



LL. Dorsal part of body flat ; beak not 

 reaching beyond second coxa. Bed- 

 bugs. (Page 1 14) ACAXTHIDAE 



