THE BROAD-HEADED BUGS. 257 



of them is by Say, 1824; Stal, 1870; Montandon, 1893, and 

 Fracker, 1918. The family is divided by recent authors into 

 three tribes, all of which are represented in the eastern states. 



KEY TO TRIBES OF CORISCID^E. 



«. Hind femora very slender, not armed beneath; cheeks, in our eastern 



species, much longer than tylus and contiguous in front of it. 



b. Fourth joint of beak at least twice as long as third, second longer 



than third and fourth united. Tribe I. Micrelytrini, p. 257. 



bb. Third and fourth joints of beak subequal, second not longer than 



third and fourth united; body and legs very slender. 



Tribe II. Leptocorisini, p. 259. 



eta. Hind femora armed beneath with one or two rows of spines ; cheeks 



shorter than tylus. Tribe III. Coriscini, p. 260. 



Tribe I. MICRELYTRINI Stal, 1867, 542. 



Of the four genera representing this tribe in the United 

 States, but one occurs east of the Mississippi. 



I. Protenor Haglund, 1868, 162. 



Elongate, very slender species having the head porrect, 

 slightly longer than pronotum ; cheeks much longer than tylus, 

 contiguous in front of it, their tips subconical and cleft hori- 

 zontally, so that the front of head ends in four short processes ; 

 antennse slender, nearly as long as body, first joint subclavate, 

 subequal to second, third slightly shorter, fourth about one- 

 half longer than second ; beak surpassing middle coxae, its third 

 joint very short ; ocelli placed close to hind margin of head, the 

 interval separating them less than one-third that between them 

 and eye ; pronotum subtrapezoidal, slightly longer than wide at 

 base, its side margins straight, entire, visibly narrowing from 

 humeri to apex; membrane shorter than abdomen, the latter 

 not wider than elytra ; legs rather short, hind femora not pass- 

 ing fourth ventral ; hind angles of metapleura subacute. Two 

 species are known. 



KEY TO SPECIES OF PROTENOR. 



a. Head less than one-fourth longer than pronotum; upper and lower 

 pair of apical processes of cheeks contiguous or nearly so through- 

 out their length. 188. belfragei. 

 aa. Head one-half longer than pronotum; upper processes of cheeks 

 widely separated from lower throughout their length. 



189. AUSTRALIS. 



