198 IOWA ACADEMY OF SCIENCES. 



species of the second group have longer pronotum, longer, nar- 

 rower elytra, with an appendix, never possessing reflexed veins. 

 Here is placed debilis, which is closely related to the European 

 a^dominalis and melscheimeri, which is intermediate between the 

 Europe in notatus and striatus. The group is nearly unicolor- 

 ous, without distinct markings; the larv» are unicolorous, usu- 

 ally yellowish in color. The third group, of which inimicus is 

 the best knov^n, have shorter, rounding, more centrally pro- 

 duced heads, with a row of points on the anterior margin of the 

 vertex, extending down to the antennae on either side. The cen- 

 tral ante apical cell is constricted in the middle and divided by 

 a short nervure. They are closely related to the European 

 puUcarius, and, like that species, not typical Deltocephalids. 

 They are of a general dark color, more or less maculate. The 

 known larvae are dark margined or banded. 



It has been thought best to place this group here for the 

 present, though in a revision of the family it may prove neces- 

 sary to establish another genus which shall include also such 

 forms as nigrifrons. 



SYNOPSIS OF AMERICAN SPECIES. 



A. Vertex strong, disk flat or concave, margin in front of eyes straight. Ocelli on 

 a level with the disk of vertex before the upper margin of eye. 



B. Pronotum short, more than twice broader than long, nearly truncate 

 behind, posterior angles obtusely rounding, side margins long, elytra 

 without a distinct appendix— light colored species with brown mark- 

 ings, larvae light, with four brown stripes. 



c. Elytra moderately long, with two outer apical veinlets strongly 

 reflexed to the costa, the next one meeting the costa at nearly 

 right angles, all three white, dark margined. 



d. Pronotum four-lined, lines sometimes coalescing, black, 

 e. Vertex longitudinally lined or else spotted, ground 



color, yellow; front, narrow hiliiieatus. 



ee. Vertex transversely lined before the eyes, gen- 

 eral color white, front broad, inflated albldus. 



dd. Pronotum cinereus, never distinctly dark-lined. 



e. Third apical cell larger than anal one, face dark 

 above, light below; species four mm. or more long, 

 f. Face light or fuscous above, shading out 

 below, no sharp line of demarkatlon, cla- 

 val veins not uniting, vertex short, nearly 

 right angled, male genitalia Inflated, plates 

 roundingly pointed; species nearly unicol- 

 orous above, except a broad spot in third 



apical cell inflatus. 



S. Face black above, white below, line of de- 

 markatlon sharp, vertex, long, acutely 

 pointed, dark markings above, sharp, veins 

 on clavus coalescing through the middle 

 third, male plates long, acutely, slightly 



concavely pointed reflexus. 



ee. Third apical cell smaller, or only equaling anal 

 one, face usually entirely dark; species less than 

 four mm. long. 



