92 Psyche [June 



19. Body convex below, flat or slightly concave above; greenish in color; clavus 



membranous, similar in texture to the membrane, the latter without veins 

 (fig. 21), corium somewhat thickened; usually wingless; ocelli distinct in 

 winged form, obsolescent in wingless form; rostrum 3-segmented; tarsi 

 3-segmented; small aquatic predatory species living generally on floating 



vegetation MESOVELIIDiE 



Body usually very thin, flat above and below; when not distinctly flattened 

 hemielytra are not constructed as above; color not greenish; terrestrial or 

 riparian 20 



20. Tarsi 2-segmented 21 



Tarsi 3-segmented 22 



21. Head wider just behind the eyes than immediately in front of them; eyes not 



projecting beyond extreme side of head (fig. 9); trochanters distinct; abdom- 

 inal spiracles midway between apex and base of ventral segments: ocelli 

 absent; rostrum apparently 3-segmented; true first segment very small, 

 often concealed; flat dark colored species living under dead bark; moderate 



in size DYSODIED.^ 



Head narrowed behind the eyes, eyes projecting strongly (fig. 10) ; trochanters 

 connate with femora; abdominal spiracles near base of segments; other char- 

 acters as in the preceding family ARADID.^ 



22. Ocelli present 23 



Ocelli absent; hemielytra always much reduced, without membrane; rostnmi 



not reaching intermediate coxae, 3-segmented; tarsi 3-segmented; parasitic 

 on vertebrates; rather small species CLINGCORID^ or CIMICIDiE 



23. Hemielytra pro\nded with a cuneus, membrane without long closed cells 



(fig. 2), sometimes without veins; occasionally brachypterous; head hori- 

 zontal; rostrum 3-segmented; tarsi 3-segmented; small predatory forms 



ANTHOCORID.E 



Hemielytra without a cuneus; membrane with four or five long closed cells 



(fig. 3); tylus separated from frons by an impressed line; always fully winged; 



predatory; littoral; moderate or small in size SALDIDiE or ACANTHIID.ffi 



24. Ocelli absent 25 



Ocelli present 27 



25. Membrane with two large cells at base from which extend about eight branching 



veins (fig. 4); hemielytra without a cuneus; rostrum 4-segmented; tarsi 



3-segmented; phytophagous; rather large strong forms . *PYRRHOCORID.ffi 



Membrane with one or two small cells at base, very rarely with longitudinal 



veins; cuneus distinct; rather small delicate forms 26 



26. First segment of rostnmi longer than broad, extending generally somewhat 



beyond posterior margin of head; membrane with two small cells at base 

 or rarely one (fig. 5); generally without longitudinal veins other than the 

 "anal" vein; rostrum 4-segmented; tarsi 3-segmented; phytophagous, or 



rarely predatory; numerous common species CAPSID.^ or MIRID.ffi 



First segment of rostrum little or not longer than broad, extending posteriorly 

 not farther than middle of eyes; membrane with one cell; rostrum 4-seg- 

 mented; tarsi 3-segmented; very few rare species. fTERMATOPHYLID.^ 



