NO. 3568 MELANOTUS — QUATE AND THOMPSON 9 



apical spui's; tarsal claws pectinate; tarsi simple, without lobes. 

 Punctures on venter of body teardrop shaped. 



Key to North American Species of Melanotus 



1. Pronotum and elytron of different colors, pronotum partly or completely 



reddish orange and elytron black 2 



Pronotum and elytron of same color 3 



2(1). Pronotum almost entirely orange and abdomen entirely black; antenna 

 of cf usually exceeding tip of hind angle by 1 segment or less, ? 



antenna ending about at tip 43. leonardi 



Pronotum black in center and orange elsewhere, and abdominal venter 

 partly or entirely orange; antenna of cf ending before tip of hind 



angle by about 1 segment and less in ? 44. taenicollis 



3(1). Antennal segments 4 and following much longer tiiau wide; antenna 

 generally extends to or beyond hind angle; not with following combi- 

 nation 4 



Antennal segments 4 and most of following wider than long, and lobes 

 lighter in color than rest of antenna; antenna ends 2 or more segments 

 before tip of hind angle; frontal margin slightly indented in center, 

 when viewed from front curves down, and hence nasale is only nar- 

 row space between frontal margin and clypeus; frontal and pronotal 

 punctures very large; Arizona to Baja California . . 45. cribricollis 



4(3). Mandible without pit on lateral, exposed margin 5 



Mandible with pit on lateral margin 21 



SiMiLis Group 

 (Mandible without pit on lateral margin) 



5(4). Antennal segment 3 small, subequal to 2 or at least much nearer size of 



2 than 4 6 



Antennal segment 3 intermediate in size between 2 and 4, clearly larger 

 than 2 8 



6(5) . Antennal segments beyond 3 triangular, same color as body, triangular, 



erect male hairs well developed 7 



Antennal segments beyond 3 testaceous, lighter in color than rest of 

 body, subquadrate, erect male hairs poorly developed; sides of pro- 

 notum with marked concavity before hind angles, angles rather small 

 and not widely divergent; cf paramere incurved near center and ta- 

 pering to point, without apical blade 15. ignobilis 



7(6). Smaller species, elytron less than 8.0 mm; frontal margin thin and 

 jutting over nasale; nasale and parantennal fovea obsolescent; sides 

 of pronotum with concavity before hind angles, angles smaU; cf 



paramere with apical blade 14. clandestinus 



Large species, elytron more than 9.0 mm; frontal margin not strongly 

 jutting over nasale; nasale and parantennal fovea poorly developed, 

 but usually present; sides of pronotum often straight and divergent 

 posteriorly with large hind angles; cf paramere with apical 

 blade 4. castanipes 



8(5). Frontal and pronotal punctures not greatly enlarged; punctures on 

 venter of abdomen oblong and lateral ones but little larger than 

 central ones; cf paramere little shorter than aedeagus and with 

 apical blades 9 



