Scarabaeidae of Nebraska 107 



Large, dark, or reddish brown species, 17-25 mm. in length 7 



6. Pronotum and elytra essentially similar in color and luster; 

 hair long, dense and erect on pronotum and head, much shorter 

 and recumbent on the elytra, except a few long hairs near 

 the base tristis 



Pronotum and elytra conspicuously different in color and lus- 

 ter, the former shining and nearly bare, the latter densely cov- 

 ered with a pale or whitish bloom, and almost devoid of luster. ..iem's 



7. Pubescence of upper surface very sparse and inconspicuous, 

 most evident on the pronotum hh^ticula comosa 



Pubescence of upper surface conspicuous 8 



8. Upper surface smooth and appearing highly polished under the 

 hand lens; both of the terminal spurs of the hind tibiae jointed 



at the base, (17-20 mm.) crenulata 



Upper surface dulled by a fine bloom, which shows a slight 

 iridescence under the hand lens; hind tibial spur next to the 

 attachment of the tarsus jointed at the base, the outer spur 

 fixed, (19-25 mm.) illicis 



9. Smaller (10-14 mm.), form slender and elongate, color yellow 



or testaceous 10 



Larger (15 + mm.), form more robust and oval, color darker, 

 reddish brown to dark brown 11 



10. Antennae always 9-jointed; fixed spur of hind tibiae of male 

 short longitarsa 



Antennae 10-jointed (rarely 9-jointed) ; fixed spur of hind 

 tibiae of male long, blunt at the apex, distinctly curved and 

 slightly twisted on its own axis gracilis 



11. Antennae 9-jointed implicita 



Antennae 10-jointed 12 



12. Males: Antennal club nearly as long as, or sometimes longer 

 than, the preceding portion of the antenna; under surface of 

 abdomen more or less flattened, grooved, or excavated on one 



or more segments 13 



Females: Antennal club much shorter than the preceding por- 

 tion of the antenna; under surface of abdomen usually smooth 

 and convex 26 



213 



