23 



Passalidae share six apomorphic character states of the wing articulation and wing base 

 with Diphyllostomatidae, Lucanidae, Glaphyridae, Trogidae, Bolboceratidae and Pleoco- 

 midae (Browne & Scholtz 1995). 



Diphyllostomatidae 



Introduction 



The Diphyllostomatidae are a monotypical family with three species endemic to the 

 western USA. Males and females are dimorphic. Males are smaller and long-winged and 

 females are larger, with reduced wings, eyes and antennae. Nothing is known about their 

 biology and the larvae are unknown. 



Diphyllostoma was described as a member of Aesalinae (Lucanidae) but since it apparently 

 has little in common with Lucanidae, Holloway (1972) elevated Diphyllostoma to family 

 status. She based this on the presence of exposed protrochantin, exposed second abdominal 

 segment, reduced female genitalia in Diphyllostoma and differences in wing venation, male 

 genitalia and leg structure between Diphyllostoma and Lucanidae. This system is currently 

 accepted by other workers in the field (Scholtz 1990). 



Holloway (1972) suggested that Diphyllostomatidae are closely related to Geotrupidae. 

 Recently, Caveney (1986) suggested, based on synapomorphic ommatidium structure, that 

 Diphyllostomatidae are probably more closely related to Lucanidae. This relationship is 

 supported by wing articulation and wing base characters (Browne & Scholtz 1995). 



Hind Wing Articulation Description 



First Axillary (Fig.3 1 ) 



Head - Dorsal surface normal size. Antero-dorsal margin normal width; weakly deplanate; 

 oriented weakly postero-distad. Po stem -proximal margin weakly enlarged proximally. 

 Proximal margin strongly enlarged ventrally. FSc2 base normal width. Apex rounded; 

 oriented postero-distad. Anterior surface broad; very long; not waisted medially. FScl very 

 weak. Ventral projection tapers from base to apex; short but of normal width; deeply 

 concave; oriented disto-ventrad and curved posteriad. Apex narrow; rounded. Concavity 

 located in the preapical area; surrounded by three unequally strong ridges of unequal 

 length. Distal embayment oriented dorsad. FSc2 deltoid; broad; very convex; oriented 

 distad and weakly dorsad; not enlarged dorsally. Head and neck dorsal surface weakly 

 curved proximad. 



Neck normal width and length; strongly curved proximad; weakly oriented antero-distad. 

 Proximal margin moderately convex. Distal margin deeply but narrowly concave; broadly 

 articulated with 2Ax. Distal embayment concave. 



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

 proximal margin concave. Postero -proximal margin convex; weakly recurved. Articulation 

 with PRR strong but short. Distal arch normal size; slightly longer than the proximal arch; 

 weakly oriented postero-proximad. Apex aciculate; weakly curved ventrad and posteriad. 

 Distal margin straight. - Ventral view: Proximal arch margined by very weak ridges. 



