1918] Barber — Synoptic Keys to the Lygmdoe (Hemiptera) 75 



C. Head more or less distinctly exserted. Pronotum with a 



constricted ring-like collar. Body more or less elongate. 

 D. Head strongly exserted, forming a short neck at base; the 

 postocular space about four times as long as the space 

 between the antenna and eye. The eyes placed about 

 midway on the head. Hind tibia provided with fine rigid 

 bristles. Basal segment of posterior tarsus about as long 

 as second and third together. Macropterous and brachy- 



pterous forms Heroeus Stal. 



DD. Head much less exserted, commonly strongly contracted 



back of eyes; postocular space commonly subequal to or 



sometimes shorter than space between base of antenna 



and eye. 



E. Anterior lobe of pronotum, especially in brachypterous 



forms, globose, almost the diameter and about twice the 



length of posterior lobe. Postocular space subequal to 



space between antenna and eye. Scutellum much 



longer than wide. Head and pronotum shining. Hind 



tibia with rigid bristles. Posterior tarsus with first 



segment nearly three times as long as second and third 



together. Macropterous and brachypterous forms. 



Sphoerobius Uhl. 

 EE. Anterior lobe of pronotum not so evidently globose and 

 narrower than posterior lobe. Head and thorax seldom 

 shining. Basal segment of posterior tarsus most com- 

 monly not more than twice as long as second and third 

 together, if three times as long as second and third then 

 the posterior tibia is provided with long rigid bristles. 

 F. Preocular space to base of antenna about three times 

 as long as postocular space; head not strongly con- 

 tracted back of eyes; apex of tylus not extended to 

 middle of basal segment of antenna; this segment in- 

 crassate and elongate, a little longer than basal segment 

 of rostrum; second segment very elongate, over twice as 

 long as the third or fourth, longer than third and fourth 

 together. Pronotum with anterior lobe twice as long 

 as posterior. Collar set off by a depressed series of 

 punctures. The anterior femora armed with two rows 

 of spines, the outer series confined to the subapex. 



