78 Key to Families of North American Insects. 



bugs. (Lygus [L. pratensis, Tarnished plant bug], Halticus, Poecilocapsus) 



(PL 14, 6g. 325.) (CAPSIDfil.) MIRIDJE 



Ocelli present; tarsi three-jointed 14 



14. Beak four-jointed; head vertical; membrane with one or two cells or one vein. 



(Isomet&pus.) ISOMETOPIIX 



Beak three-jointed; head horizontal; membrane with four to one longitudinal 

 veins which are rarely entirely lacking. (Anthocoris, Tnphleps [T. insid- 

 wsus, Predatory flower-bug]) (PL 14, fig. 337) ANTHOCORID^ 



15. Claws subapical; hind coxae distant; hemelytra of uniform texture, the clavus, 



corium and membrane confluent 16 



Claws apical 17 



16. Beak four-jointed, but the first joint short; middle and hind legs close together, 



distant from the front ones and much longer than the latter. 

 Water striders. (Gems (= Limnotrechus)) (PL 14, fig. 327) HYDRO- 

 BAUD^ GERRIDjE 



Beak three-jointed; middle legs almost as distant from the front as from the 

 hind ones. (Microvelia, Rhagovelia.) VELIUXE 



17. Prosternum without a stridulation groove 18 



Prosternum with a median stridulation groove; beak three-jointed, short and 



stout 25 



18. Ocelli absent; beak three-jointed 19 



Ocelli present, when very rarely absent, the beak is four-jointed and the 



head is not apically widened 22 



19. Tarsi three- or four-jointed 20 



Tarsi two-jointed; broad, flat species living under bark; head produced between 



antennas; abdomen broader than the wings 21 



20. Body, linear; head horizontal, as long as the thorax and widened toward the 



apex. Marsh treaders. (Hydr6metra (= Limnobates}) (PL 14, fig. 326). 



(LIMNOBATID&) HYDROMETRHXE 



Body oblong; head broad, triangular, shorter than thorax; eyes absent; no 

 scutellum; hemelytra short, destitute of membrane; parasitic on bats. 

 (Hesper6ctenes) (PL 14, fig. 333) POLYCTENID^E 



21. Head not wide behind the eyes which are prominent; beak longer than the 



head; trochanters very short, fusing with the femora; abdominal spiracles 

 placed near the base of the segments. (Aradus) (PL 14, fig. 335). 



ARADHXE 



Posterior part of head wide, enclosing the eyes, often spinose, beak rarely 

 longer than the head; trochanters distinct; abdominal spiracles remote 

 from the base of the segments. (Aneurus, Mezira.) DYSODfflXE; 



22. Beak four-jointed, with the first joint small; last joints of the antennae more 



slender; membrane with two or three longitudinal cells emitting radiating 



veins. (Reduviolus, Pagasa.) NABnXffi 



Beak three-jointed 23 



