89 



Rutelinae + Dynastinae (Ritcher 1969a,b; Yadav & Pillai 1979; Meinecke 1975; Caveney 

 1986: Scholtz 1990; Lawrence & Britton 1991). 



Melolonthinae share 22 apomorphic character states of the wing articulation and wing base 

 with Orphninae. Rutelinae, Dynastinae. Cetoniinae, Oncerinae, Chasmatopterinae, Acoma, 

 Hopliinae, Trichiinae and Valginae (Browne 1993). 



Acoma 



Introduction 



Acoma is a small genus which occurs in the western United States (Howden 1958; Ritcher 

 1969a,b). Acoma is a well defined genus of uncertain phylogenetic status (Ritcher 

 1969a,b). Both Arrow (1912, in Ritcher 1969a.b) and Leng (1920) placed Acoma in 

 Pleocomidae. Davis (1924, in Howden 1958) thought Acoma belonged near Podolasia 

 while Blackwelder (1944) listed it in the tribe Chasmatopterini of the subfamily 

 Melolonthinae. Howden (1958) stated that the phylogenetic placement of the genus is 

 likely to remain in doubt until the morphology of the female is known. Ritcher (1969a,b) 

 has suggested that Acoma is related to one of the scarab subfamilies, but he does not 

 elaborate. 



Hind Wing Articulation Description 



First Axillary (Fig. 143) 



Head - Dorsal surface strongly reduced posteriorly; broad; clavate; convex. Antero-dorsal 

 margin oriented weakly postero-distad; normal width; very convex. Antero-proximal 

 margin with ventral enlargement reduced. Postero-proximal margin enlargement moderate 

 and broad. FSc2 base weakly enlarged; deeply concave. Apex oriented postero-distad; 

 rounded but narrowly so. Anterior surface narrow; long; waisted medially. FScl absent. 

 Ventral projection long and narrow; enlarged mesally; deeply concave; oriented ventrad 

 and weakly postero-distad. Dorsal surface base to median concave. Ventral surface convex. 

 Apex wider than base; strongly flared; truncate. Concavity basad and moderately extended 

 apicad from the base of the ventral projection; surrounded by three unequally strong ridges. 

 Distal embayment oriented ventro-mesad. FSc2 oriented distad and weakly dorsad; deltoid; 

 convex; broad; moderately short. Dorsal surface enlarged dorsally; convex; appears 

 twisted. Ventral surface convex. Base proximally with a large convexity. Apex aciculate. 

 Head and neck dorsal surface extended anteriad. 



Neck normal width; long; weakly oriented antero-distad; articulation with 2Ax extends 

 along the distal margin of the neck and tail; continuous with tail. Proximal margin reduced; 

 sinuate; not curved ventrad. Distal margin concave. Distal embayment moderately concave; 

 moderately shallow but broad. 



Tail - Dorsal view: Proximal arch normal size. Dorsal surface weakly concave. Antero- 

 proximal margin weakly convex. Postero-proximal margin straight. Articulation with PRR 

 strong along the entire length of the proximal arch; very long but narrow; weakly recurved. 

 Antero-dorsal surface concave. Postero-dorsal surface concave. Posterior margin weakly 



