350 TERTIARY INSECTS OF NORTH AMERICA. 



moderately large eyes at the very base. Antenna? four-jointed, about reach- 

 ing to the base of the middle legs, the -joints of nearly equal length, but the 

 first and fourth a little the longest and the second shortest, the first cylin- 

 drical and moderately stout, the last oval, the others obovate and a little 

 slenderer. Pronotum faintly set off from the rest of the thorax as a trans- 

 verse piece more than twice as broad as long, the thorax as a whole pentag- 

 onal, the posterior border being subangulate and the posterior sides of the 

 pentagon only slightly oblique ; front margin straight and longer than any 

 of the others, though the thorax narrows forward rather rapidly. Legs short 

 and stout, the fore legs about half as long as the others, the hind pair the 

 longest, though the middle and hind femora are subequal ; the hind tibiae 

 longer than the middle tibia? or than the femora, while the femora and tibia3 

 are equal in the fore and middle legs, or the tibia is only slightly longer 

 than the femur in the middle legs ; tarsi three-jointed, the joints tolerably 

 long, the last a little shorter than the others. Abdomen oval, well rounded, 

 the last two joints sometimes produced. No trace of wings. 

 A single species is known. 



STENOVELIA NIGRA. 



PI. 22, Figs. 8, 14. 



Whole body uniformly dead black ; the pigment in some cases has 

 broken in flakes from the legs, especially the middle and hinder pairs, giving 

 them a mottled appearance which is purely accidental. The whole body, 

 including the legs, uniformly smooth, with no trace of hairs or spines. 



Length of body, 3.75 mm ; breadth, l.GS 1 ; length of antenna?, l.l mm ; 

 fore femora, 0.75 mm ; tibiae, 0.75 1 "" 1 ; tarsi, 0.35 mm ; middle femora, 1.2 mm ; 

 tibiae, 1.3 mm ; tarsi, 0.8 mm ; hind femora, 1.2 mm ; tibia?, 1.4 mm ; tarsi, 0.8 mm . 



Florissant. Twenty-three specimens, Nos. 875, 878, 1934, 2936, 3020, 

 3268, 3866, 6497, 7565, 9243, 9499, 9563, 9589, 10344, 10691, 10787, 

 10945, 12074, 12098, 12099, 12936, 14025, 14981. 



Family HYDROBATID^ Stal. 



This family was perhaps known in Mesozoic times. Oppenheim, 

 indeed, figures two species which he refers to a. new genus Halometra, sup- 

 posed to belong here, but which Deichmiiller has shown should be referred 

 to the Acridii, among Orthoptera. Perhaps here, however, belong unfigured 

 and undescribed forms from the English rocks referred by Westwood to 



