The Psei.aphid^ of North America. 3 



base, half as long as the width of the segment. Sexual dif- 

 ferences confined to the structure of the vertex, the antenna, 

 and the last ventral segment. Palpi with the third joint glob- 

 ular, fourth oblong ovate, yellow. 



V. CORNUTUS, Brendel. Dark yellow, fainth' punctulate, 

 thinly pubescent with recumbent hair. 



Head square, corners rounded, eyes with coarse facets. 

 Prothorax subglobose. Elytra slightly flattened at the base, 

 without basal punctures, the discal lines indicated by very 

 short impressions, the sutural entire, straight. First abdomi- 

 nal segment one-fourlh as long as wide, with a transverse 

 linear bar at the base. Legs long, simple. 5 head^ occiput 

 elevated, produced into two horizontal horns which are sepa- 

 rated by a deep emargination, and overhang the surface of 

 the vertex. The plane of the vertex is uneven, pubescent, 

 with six punctures arranged in a circle; in the frontal angles, 

 posterior to the slightly elevated antennal tubercles are two 

 small spinul^e. Antennce ten-jointed, first joint sub-cyHndri- 

 cal, half as long as the frontal margin; second similar, slightly 

 smaller; third short, rounded, half as long as the second: 

 fourth as long and thick as the first; fifth, sixth, and seventh, 

 obconical, shorter, as thick as the third; eighth and ninth 

 obconical, rounded. Prothorax as long and wide as the head, 

 eyes included, and with a small puncture at the base. Last 

 ventral segment with a deep circular impression. ? head 

 slightly convex, eyes less prominent, vertex with two small 

 punctures between the eyes, mutuall}' three times as distant 

 as either from the eye, and two smaller punctures near the 

 antennal tubercles, a faint line connecting the four punctures. 

 Frontal margin straight. Antennm eleven jointed, first joint 

 half as long as the frontal margin, obconical; second as wide 

 as the first and half as long, obconical; third to eighth small, 

 nearly globular; ninth and tenth gradually larger, trapezoi- 

 dal; eleventh as long as the three preceding joints, and twice 

 as wide as the tenth, oblong ovate; the fourth joint of the 5 

 shows a transverse line indicating ankylosis of two joints. 



