164 THE UNIVERSITY SCIENCE BULLETIN. 



KEY TO SPECIES. 



A. Robust forms; female segment with large median lobes, pygofers 

 of male rounded. robusta. 



AA. More slender forms; female segment with a very short or no median 

 lobe in the broad excavation, pygofers of male acute, ending in long 

 chitinous processes. argenteolus. 



Aconura robusta (Bak.). 



Athysanella robusta Bak., Psyche, viii, p. 187, 1898. 

 Aconura robusta Van D., Cat. Hemip. N. A., p. 653, 1917. 



Form: Bread and robust. Length, 3 to 4 mm. Vertex short, half 

 broader than long, transverse depression distinct, very obtusely angled. 

 Pronotum short, nearly three times as wide as long, lateral margins long, 

 humeral margins indistinct, appearing like part of the medially emargi- 

 nate posterior margin, covering the base of the elytra and the scutellum, 

 making the latter appear small. Elytra short, reaching just beycnd third 

 abdominal segment, rounded apically, venation weak. 



Color: Grayish-yellow; vertex lighter than rest of body, with small to 

 large brown spot near margin half way between eye and apex. Pronotum 

 and elytra in specimens at hand unmarked. Abdomen usually with 

 transverse row of dark spots on anterior portion of each segment and 

 with faint longitudinal lines. 



External genitalia: Female, last ventral segment deeply emarginate 

 between the long acute lateral angles, with a distinct tooth in the emargi- 

 nation, which, in our forms, does not reach quite half way to the tips of 

 the lateral angles; pygofers long and narrow, very sparsely bristled, 

 greatly exceeded by the very long ovipositor. Male, last ventral segment 

 posteriorly emarginate; valve small, obtusely angled; plates broad and 

 short, diverging, broadly rounding apically; pygofers broadly rounding 

 apically. Apex of hind tibiae with a large, acutely pointed, dorsal spine, 

 which reaches to about the middle of the first tarsal segment. 



Distribution: Specimens are at hand from Ottawa county. 

 Hosts: Taken in pastures where buffalo grass and Bouteloua 

 abound. 



Aconura argenteolus (Uhl.). 



Deltocephalus argenteolus Uhl., Bui. U. S. Geol. Surv., iii, p. 473, 1877. 

 Deltocephalus argenteolus Bak., Psyche, viii, p. 119, 1897. 

 Aconura argenteolus Horv., Ann. Mus. Natl. Hung., vi, p. 567, 1908. 

 Aconura argenteolus Van D., Cat. Hemip. N. A., p. 653, 1917. 



Form: More slender than preceding species. Length, 2.75 to 4.5 mm. 

 Vertex as long or slightly longer than wide, transversely depressed, more 

 pointed apically than robusta. Pronotum shorter than vertex, anterior 

 margin convex, lateral margins parallel and long, humeral margins fus- 

 ing with slightly concave posterior margin. Elytra short, covering third 

 abdominal segment, or long, reaching to pygofers, there being both 

 macropterous and brachypterous forms in both sexes, venation weak. 



