348 TERTIARY INSECTS OF NORTH AMERICA. 



as broad as their tibise, which equal or surpass them in length, the fore 

 femora considerably longer than tlie middle pair ; all the tarsi equal, but 

 the fore tarsi two-jointed, the others three-jointed, the joints of each sub- 

 equal. 



This genus differs markedly from Pelogonus, to which it appears to be 

 the most nearly allied, in the great length of the fore legs, which seem to 

 show a relationship to the Naucoridoe, though they are in no sense rajJtorial. 

 It is also peculiar for the want of eyes upon the upper surface of the head. 

 The legs are smooth. 



A single species is known. 



Necygonus rotundatus. 

 PI. 7, Fig. 8. 



Although the abdomen is wanting, the form of the anterior part of the 

 body, witli the anterior position of the legs, would indicate that the creature 

 was of a short oval form, very likely twice as long as broad. The flat 

 body, both head and thorax, are of a slightly granular texture, and of a 

 dusky color, uniform for body and legs, except that the head is slightly 

 darker than the rest. 



Breadth of body, 3.5"°"; head, 2.5°"°; length of head, l"""; rostrum, 

 2.6""; antennae (as far as preserved, detached from the body), 4™"'; fore 

 femora, 3.25"™; tibiae, 3.75""; tarsi,!""; middle femora, 2.75""; tibiae, 

 2.65"" ; tarsi, 0.9"" ; hind tarsi, 1.2"". 



Green River, Wyoming. One specimen. No. 107, Dr. A. S. Packard. 



Family VKL^WDJE Douglas and Scott. 



Westwood states that species allied to Velia occur in the Secondary 

 rocks of England, but there is no figure of them, and this is the only men- 

 tion of their occurrence before the Tertiaries. Similarly their only mention 

 in the later series is by Serres, who says that at Aix a species of " Gerris' 

 occurs which he compares to Velia currens. In our own Tertiaries two 

 species have occurred, at Florissant, each ajjparently belonging to a dis- 

 tinct and extinct genus ; these I have called Palaeovelia and Stenovelia. 



Table of the. genera of Veliidw. 



Hiud tibifB and first tarsal joint armed at tip with long spines 1. Palaovelia. 



Hind tibiiB and first tars.al joint not armed at tip with long spines - 2. Stenovelia. 



