1	Metasomal tergite I with slight constriction in width nearer anterior end and very long (at least 2 × as long as apically or basally broad); metasomal tergite II (raised part) rather parallel-sided and close to 2 × as long as broad; propodeum usually with median longitudinal carina pronounced in the anterior third, sometimes percurrently	2
–	Metasomal tergite I without obvious narrowing near anterior end, either posteriorly narrowing throughout, or broadening generally and usually less than 2 × as long as broad; metasomal tergite II less than 2 × as long as broad, variably shaped; propodeum usually without obvious medial longitudinal carina, or with only a stub of one posteriorly or anteriorly	Here it continues to couplet 3 of Whitfield et al. (2011), including all remaining known species of Venanus
2	Female body length 2.8–3.0 mm; propodeum with median longitudinal carina marked throughout most of its length, strongly so on anterior 0.3; T2 length 2.5 × its central width [Colombia, Ecuador]	Venanus helavai Mason, 1981
–	Female body length at most 2.5 mm (usually less); propodeum with median longitudinally carina only slightly marked on anterior 0.3, or not clearly defined (carina not distinct among other sculpture of propodeum); T2 length less than 1.8 × its central width [Costa Rica, Ecuador]	3
3	Fore wing with first discal cell width 1.0 × its height, and vein 2RS shorter than r; anterior half of propodeum mostly smooth (only with fine rugulosity medially and laterally); metasoma with most laterotergites black [Ecuador, specimens collected at or over 2,100 m]	Venanus yanayacuensis Arias-Penna & Whitifield, 2011
–	Fore wing with first discal cell width 1.2 × its height, and vein 2RS significantly longer than r; anterior half of of propodeum as coarsely rugose as posterior half (at most with smooth area partially on anterior 0.1–0.2 of propodeum); metasoma with most laterotergites brown [Costa Rica, specimens collected at 1,400–1,460 m]	4
4	Fore wing with length of vein 2RS 1.4 × length of vein r; metapleuron coarsely sculptured on posterior 0.3 × (in addition of strong impressions on posterior margin); T2 coarsely rugose; T1 relatively less constricted than below, with T1 narrowest width (near anterior margin) 0.8 × width at posterior margin	Venanus randallgarciai Fernández-Triana & Whitfield, sp. n.
–	Fore wing with length of vein 2RS 2.0 × length of vein r; metapleuron mostly smooth (except for strong impressions on posterior margin); T2 smooth; T1 relatively more constricted than above, with T1 narrowest width (near anterior margin) 0.6 × width at posterior margin	Venanus johnnyrosalesi Fernández-Triana & Whitfield, sp. n.

Both species from Costa Rica will run through couplet 2 of the key in Whitfield et al. (2011). The key below separates the new species from those mentioned in that couplet.