OSBORN AND BALL —STUDIES OF NORTH AMERICAN JASSOIDEA. 89 



length of the abdomen, d", valve short, rounding, sometimes almost 

 concealed by the broad ultimate segment, plates broad at base, the 

 inner margins rounding, outer margin emarginate and impressed near 

 the middle, tips obtuse, widely separated. 



Described from eight examples from Sioux City and Little Rock, 

 Iowa, collected by the authors, and four examples from Colorado, re- 

 ceived from Prof. Gillette. 



Larva : Similar in form to adult, reddish-brown with light markings, 

 a light band on the face as in adult and another on the fourth abdo- 

 minal segment, vertex slightly longer and more angled than in the 

 adult, reddish-brown irregularly maculate, usually a pair of light spots 

 between three dark ones on the anterior margin and a lighter spot 

 against either eye, pronotum dark-brown with the anterior margin 

 Irregularly light, wing-pads brownish with a light spot just inside the 

 posterior angle. Abdomen reddish with four longitudinal rows of light- 

 colored bristle-bearing papillae, transverse light bands occupying fourth 

 segment continuing obliquely backward under the margin on either 

 side of the seventh. Below, dark, a transverse light band on face 

 below eyes as in adult; legs dark brown or black, fore and middle 

 tibiae and a narrow line including the spines on posterior tibiae yellow. 



Life History: The species is probably two-brooded as larvae and 

 freshly issued adults were collected the first week in July, and larvai 

 again late in the fall, indicating a liie history very similar to that of 

 gammaroidea. 



Driotura GAMMAROIDEA V. D. (Plate IV, Fig. 3.) 



Short compact form with a bluntly conical head, stout body and a 

 broad convex abdomen, in the female tipped with a long exserted 

 ovipositor. Length, $ 3.5-4 mm; cJ^, 3 mm. Width, i. 25-1. 5 mm. 



Brachypterous form : Vertex twice wider than long, the anterior mar- 

 gin slightly more convex than the posterior; front obtusely convexly 

 inflated above, not so strongly as in robusta, ocelli distinctly on the 

 dorsal aspect ; clypeus oblong, parallel-margined, medially carinate on 

 the basal portion ; eyes wedge-shaped, narrowing outwardly ; pronotum 

 short, transverse; posterior margin nearly straight and overlapping the 

 elytra, lateral margin compressed anteriorly beneath the curvature of 

 the eye, posteriorly broader and extending around to the genae below. 

 Elytra coriaceous, coarsely rugose, convex, their costal margin enclos- 



