Hemiptera. 79 



23. Head not constricted at the base behind the eyes ....................... 24 



Head constricted at the base and behind the eyes, swollen between; pronotum 



divided into three lobes; hemelytra wholly membranous, provided with 

 longitudinal veins and a few crossveins; front tibiae swollen; front tarsi 

 one-jointed, hind tarsi two-jointed. (Henicocephalus) (PI. 14, fig. 336). 



HENICOCEPHALnXE 



24. First joint of antennae longer than the second; hemelytra with submembra- 



naceous corium with elevated veins, the clavus and membrane membra- 

 naceous, confluent, the latter destitute of veins. (Mesovelia.) 



First joint of antennae shorter than the second; hemelytra with distinct clavus, 

 corium and membrane, the latter with four or five contiguous longitudinal 

 cells; eyes large and projecting; small, flattened forms. Shore-bugs. 

 (Acanthia (= Soldo).) (PI. 13, fig. 315.) .... (SALDID&) ACANTHmXE 



25. Antennae elbowed, filiform or often slender apically; membrane with two or 



three large basal cells ............................................. 26 



Last joint of antennae knobbed or enlarged in the middle; membrane with the 

 veins joined, frequently forked and uniting; tarsi two-jointed; front legs 

 formed for grasping, the femora much thickened. (Phymata.) 



(PHYMATIDM) MACROCEPHAim& 



26. Rather robust, predatory species, body not linear. Assassin bugs. (Melano- 



lestes [M . picipes, Kissing bug], Conorhinus [C. sanguisugus, Big Bedbug], 

 Sinea) (PI. 13, figs. 316, 193; PL 14, fig. 338) ..'... ...... REDUVmXE 



Linear species with excessively long and thin legs. (Emesa.) . .EMESIDJE 



27. Head not shield-like, the margins usually obtuse; antennae completely visible 



from above ...................................................... 28 



Head more or less expanded, the side margins acute in front of the eyes; at 

 least the first joint of the antennae not visible from above; membrane with 

 several veins .................................................... 36 



28. Antennae five-jointed, the second joint short; clavus membranous, largely 



confluent with the membrane which is destitute of veins; tarsi two-jointed. 

 (Nseogeus.) .............................. (HEBRIDM) NMOGEIDM 



Antennae four-jointed ................................................ 29 



29. Ocelli absent ...................................................... .30 



Ocelli present ....................................................... 31 



30. Hemelytra of the fully winged forms consisting of clavus, corium and mem- 



brane; beak free; tarsi three- join ted; stout bugs of moderate size. (Dys- 

 dercus [D. suturellus, Cotton Stainer]) ............. . .PYRRHOCORID^ 



Hemelytra wholly membranous, densely reticulated; cheeks entirely raised, 

 forming a groove which includes the base of the beak; tarsi two-jointed; 

 flat bugs of small size. Lace-bugs, (Corythftca [C. arcuata, Hawthorn 

 Lace-bug]) (PI. 14, fig. 340) .............................. TINGITID^B 



81. Membrane with many longitudinal veins which often unite; antennae inserted 

 well up on the sides of the head .................................... 32 



Membrane with at most five veins ... .... 34 



