438 GEOLOGICAL SURVEY OF THE TERRITORIES. 



surface of the femora is sparsely scabrous," I liave not noticed this to 

 be the case with the '' dorsum," as stated by Haldeman. 



Bradtporini. 



Anabrus sim])lex, Hald. 



Found in great abundance between Brigham City, Utah, and Fort Hall, 

 Idaho. Also occasionally met with farther south in Utah and north of 

 Fort Hall to the boundary line of Montana, which is here along the 

 range separating the waters of the Atlantic from the Pacific. At some 

 points we found them so abundant as literally to cover the ground. In 

 two or three instances they all appeared to be moving in one direction, 

 as if Impelled by some common motive. I recollect one instance on 

 Port NeufEiver, where an army was crossing the road; it was probably 

 as much as two hundred yards in width; I could form no idea as to its 

 length; I only know that as far as I could distinguish objects of this 

 size, (being horseback,) I could see them marching on. I think that in 

 all the cases where I saw them thus moving, it was toward a stream of 

 water. They appear to be very fond of gathering along the banks and 

 in the vicinity of streams. In the north part of Cache Valley I fre- 

 quently noticed the ditches and little streams covered with these 

 ^insects, which, having fallen in, were floating down on the surface of 

 the water, and, though watching them for hours, they would flow on in 

 an undiminished stream. 



While encamped on a little creek near Franklin, in this valley, it was 

 with difficulty we could keeiD them out of our bedding; and when we 

 went to breakfast v^e found the under side and legs of the table and 

 stools covered with them, all the vigilance of the cook being required 

 to keep them out of the victuals. 



But the strangest part of its history is that it will go in pursuit of and 

 catch and eat the Cicada. This latter insect also made its appearance 

 in this valley the past season in immense numbers, covering the grass 

 and sage and other bushes, especially those which formed a fringe along 

 the little streams. Up these the Amibrus would cautiously climb, 

 reach out Avith its fore leg and plant its clav/ in its victim's wing ; 

 once the fiital claw secured a hold, the Cicada was doomed, for without 

 ceremony it was at once sacrificed to the voracious appetite of its cap- 

 tor. No uniformity appeared to be preserved in this process ; sometimes 

 they would commence with the thorax, at others v/ith the head, not even 

 taking the trouble to remove the legs or wings. 



I noticed in the road, where one of the armies was crossing, a num- 

 ber of large hawks feasting themselves upon the helpless victims. As 

 I returned through Malade Valley, (August 20, 1871,) the females were 

 depositing their eggs. They press the ovipositor perpendicularly into 

 the ground almost its entire length. PI. I, fig. 1. 



A. imrpurascens, Uhler. 



Syn.j Thamnotrizon pupurascens, Tlios. 



I have found no specimens of this species west of the Eocky Mount- 

 ain ; yet it may possibly be found on the higher plateaus. 



In my paper (Proc. Acad. IsTat. Sci. Phila., 1870, p. 76, and Eep. U. S. 

 Geol. 8urv. Wyom. Ter., 1870, p. 268) I removed this species from Ana- 

 hrus to Thamnotrizon, because the prosternum is unarmed. I did this 

 because A. Haldemannii, Girard, of which I had several specimens, has 

 the prosternum distinctly spined, and in other respects differs from the 



