WICKHAM: FOSSIL ELATERIDAE OF FLORISSANT. 523 



eleventh much longer than the tenth. Eyes not strongly convex. 

 Prothorax a little broader than long, slightly narrower at apex than 

 at base, front angles acute, sides gently and almost regularly arcuate, 

 faintly sinuate in front of the hind angles which are acute and feebly 

 divergent. The thoracic apex seems hardly emarginate, the base is 

 notched in front of the scutellum and sinuate each side. Punctuation 

 of pronotum close, deep, and rather coarse over the entire surface, 

 the punctures everywhere separated by much less than their own 

 diameters and but slightly less crowded along the median line than 

 at sides, each with a central mark which looks as if it may have been 

 the point of insertion of a hair or scale. Scutellum oval, much longer 

 than wide, coarsely punctured. Elytra moderately tapering, not 

 pointed at apices, confusedly but in general evenly punctured except 

 that the punctures become somewhat more sparse posteriorly where 

 they are separated by spaces about equal to or a little more than their . 

 own diameters. Each puncture carried a moderately long, curved 

 dark hair, giving a somewhat shaggy appearance to the surface. 

 Underside of body well preserved, showing the following features : 

 prothoracic flanks finely and densely punctured, prosternum, includ- 

 ing the spine, more coarsely and deeply; lobe strong, rounded; 

 sutures double, nearly straight, excavate anteriorly; meso- and 

 metasternal areas similarly but in general less closely punctate, coxal 

 plates narrow, little dilated externally, with a rounded lobe over the 

 insertion of the thighs; abdominal punctuation rather fine but deep, 

 closer externally but everywhere well separated. Legs not well 

 displayed. Length, from front of head to tip of abdomen, excluding 

 sex organ, 14.25 mm.; of prothocax, along median line, 3.35 mm.; 

 of elytron, 9.00 mm.; of antenna, 3.65 mm.; width of prothorax, 

 3.75 mm. 



Described from one specimen, with counterpart. 



Type. In the collection of H. F. Wickham. Wilson Ranch, 

 Florissant, Colo. 



This is probably the finest and best preserved specimen I have 

 seen among the Elateridae of the Florissant shales. The aspect is 

 much like that of a Ludius or of a Megapenthes, like the recent west- 

 ern North American M. aterrimus, but the form of the coxal plates 

 indicates a position with the Corymbitini. The punctuation does 

 not agree with that of any species of the group known to me and 

 serves at once to differentiate it from all the Florissant fossil Elateridae 

 of similar size. The antenna and sex organ are omitted (Plate 4, 

 fig. 7) but the former is shown (Plate 4, fig. 8). 



