89 (86) Elytron bimaculate 92 



Elytron with an elongate humeral spot or with a 



vitta extending from humerus almost to apex 90 



90 (89) Large, 2.8-3.1 mm long, 1.4-1.5 mm wide; elytral 



vitta extending almost to apex, at times bright 

 yellow; pronotal carinae rather short and feeble 

 (Fig. 84) : Optioservus fastiditus 



Smaller, less than 2.7 mm long; pronotal carinae 



well developed and extending at least to basal third.... 91 



91 (90) 



In far west; elytron with elongate humeral spot or 



short vitta (Fig. 85); elytra with grizzled appearance 

 due to long golden hairs; 2.1-2.5 mm long, 0.9-1.4 mm 

 wide: Optioservus aanus 



Eastern; elytron with vitta from humerus almost to 

 apex (Fig. 86); not grizzled; 2.3-2.6 mm long, 

 1.2-1.3 mm wide: Optioservus amptiatus 



Figs 83-89 Outline of adult pronotum and elytron of Optioservus 

 species: 83- 0. ozarkensis; 84- 0. fastiditus; 85- 0. aanus; 

 86- 0. amptiatus; 87- 0. ovalis; 88- 0. quadrimaaulatus ; 

 89- 0. seriatus (all from Collier). 



92 (89) Eastern; elytral spots almost forming a vitta in some 



specimens (Figs 75, 87); 2.4-2.6 mm long, 1.2-1.4 mm 

 wide : Optioservus ovalis 

 Western; elytral spots widely separated 93 



93 (92) Relatively broad, elytra noticeably wider than pronotum; 



humeral spot larger, usually reaching second stria 

 (Fig. 88); 1.8-2,2 mm long, 1-1.1 mm wide: 



Optioservus quadrimaaulatus 

 More elongate, elytra scarcely wider than pronotum; 



humeral spot narrower, usually not reaching medially 



beyond third stria (Fig. 89); 1.8-2,2 mm long, 0.8- 



. 9 mm wide : Optioservus seriatus 



45 



