20 TERTIARY RHYNCHOPHOROUS COLEOPTERA. 



half as long again as their greateHt width, punctate like the pruthorax, but 

 the puncta here with a longitudinal ai-rangement, and besides each elytron 

 has two rows of conspicuous punctate stride, one near the middle of the elytron 

 feding apically, the other nearer the sutural margin than the median stria, 

 and meeting next the tip of the elytron the apex of a slight submarginal 

 ridge. 



Length of elytra, 2 -Try'"". 

 Roan mountains, western Colorado, from the most prolific insect bed, just 

 beneath the topmost layers. Two specimens, Nos. 295, 303, U. S. Geologi- 

 cal Survey. 



ISOTHEA (eiGGoOdco), gen. nov. 



The head in this genus is of exceptional length, being slightly longer 

 than the rostrum, and with it two-thirds as long as the rest of the body; it 

 tapers regularly, but with full sides, to the rostrum which is stout, fully one- 

 fourth the breadth of the head. Antennaj almost as long as the greatest 

 width of the body, fully a third longer than the beak, joints 1-2 subequal, 

 slightly shorter and a little stouter than thoSe succeeding, 3-5 longest, 6-8 

 about half as long as 1-2, 9-11 large and broad, forming an open clul), of 

 which 9-10 are twice as broad at apex as at base, subtriangular and trun- 

 cate, the terminal joint obovate. Eyes large, lateral, not very prominent. 

 Legs somewhat shorter than in Rhynchites, but with identical form, includ- 

 ing the tarsal joints, unless the penvdtimate joint is more deeply bilobate. 

 Structure of elytra indeterminable. T'hird ventral segment of abdomen dis- 

 tinctly shorter than the second. 



The form of the body in this genus is somewhat elongate but not par- 

 allel-sided, showing a somewliat oval outline and being broadest in the 

 middle of the abdomen. 



A single species occurs at Florissant. 



IsOTHEA ALLENI. 



PI. IV, Fig. 2; PI. VIII, Fig. 1. 



The specimen, admirably pi'eserved ii^ most of its details, lies upon its 

 back, so that the sculpturing of the elytra can not be determined. The 

 head is transversely and ratlier delicately striate, the striaj turning some- 



