1918] Barber — Synoptic Keys to the Lygcridw (Hemiptera) 81 



and several smaller teeth distributed along almost entire 

 length. Clavus with three rows of punctures, the middle 

 series abbreviated. Macropterous forms only. 



Peritrechus Fieb. 

 CC. Pronotum with both lobes concolorous or nearly so, most 

 commonly ferrugineous or castaneous, rarely black, most 

 commonly shining or somewhat so. Scutellum not bivit- 

 tate with pale. 

 D. Third ventral suture of the abdomen straight and reach- 

 ing the lateral margin. Head across eyes distinctly 

 narrower than anterior margin of pronotum. Pronotum 

 with lateral margins more or less strongly keeled, with 

 impunctate anterior lobe as wide or wider than the much 

 shorter posterior lobe. Scutellum subtrans verse. Clavus 

 broad, not deflected to the corium, sometimes connate 

 with the corium. Membrane usually abbreviated or 

 wanting. Only brachypterous forms known to me. 



Plinthisus Latr. 

 DD, Third ventral suture of the abdomen curved anteriorly 

 and not reaching the lateral margin. Head across eyes 

 as wide or most commonly wider than the anterior margin 

 of the pronotum, most frequently as wide as across 

 rounded submargin. 

 E. Pronotum with both lobes very distinctly and closely 

 punctate and at the same time with the lateral margins 

 evidently carinate. Scutellum longer than wide. Fore 

 femora unarmed. 

 F. Lateral margins of pronotum more strongly carinate. 

 Eyes more projecting. Pronotum and hemielytra not 

 pilose. Clavus with three rows of punctures. 



Acompus Fieb. 

 FF. Lateral margins of pronotum narrowly carinate. Eyes 

 less projecting. Pronotum and hemielytra pilose. 

 Clavus with four series of punctures. 



Stygnocoris D. and S. 



EE. Pronotum with the entire anterior lobe or the disk only 



impunctate; lateral edge either very finely carinate or 



the propleura linearly and longitudinally impressed 



within the lateral margin. Scutellum equilateral. 



