362 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



numerous, and MesotJwmis longipennis Burm. Several kinds of Gomjjhina 

 and jEsclince were also seen, but they could not be captured, and the 

 species could not be recognized. 



Bijitera were very numerous everywhere, but a little less so in the 

 caiions. Wherever flowers were in bloom, specimens were found resting 

 upon or flying about them. Bomhylius, Anthrax, and Asilidce were seen 

 in every locality; but on the sandy plains, where plants were numerous, 

 they were astonishingly frequent. The colors and forms of most of 

 these were quite attractive, and strongly set in relief by the green color 

 of the plants ; they added much to the lively effect of the scene. Some 

 of the species did not extend south of Colorado Springs, while others 

 were seen only in Clear Creek CaQon. 



The beautiful Osjjriocems ceacus Wied. was met with singly in a few 

 places south of the divide, but near Denver it was replaced by an Asilus, 

 having a dull brown thorax, with four curving pale lines on the dorsum, 

 with smoke-brown wings and short, slender, tapering antennae, and with 

 narrower wings than the preceding. Both of these forms are very at- 

 tractive, and strongly resemble Midas, as well in their manner of flight 

 as in the scarlet abdomen with red base and tip. When in repose, the 

 red color of the body is concealed by the wings, but when flying it is 

 very conspicuous and in strong contrast with all of its surroundings. I 

 was much struck by the method which the former sometimes adopts to 

 conceal itself from a pursuer. On a hill-side not far from Colorado 

 Springs, I started a specimen while using my sweeping-net. At first, it 

 rose three or four feet in the air, and then flew off with rather heavy 

 but direct flight toward the thick patches of weeds and grass. As I no- 

 ticed where it lodged and followed closely, it again rose and flew off 

 to a distance of somewhat more than a rod. After repeating this three 

 times, and finding itself still pursued, it flew to a lot of scattered stones, 

 some of which were of a dark granitic rock, mixed largely with crystals 

 of reddish felspar, and settled upon a dark spot of one of the pieces, 

 which so well accorded with its color that only with great difficulty 

 could I detect it. 



Lordotus (j'lbhus Loew was quite rare, being seen in only two or three 

 places near Colorado Springs. The beautiful golden fur which covered 

 its whole body shone with high luster in the sunlight, and foiled the 

 yellow color of the sunflowers upon which it settled. A very beautiful 

 Mallophora, coated with bright, silky, yellow plush, occurred sparingly 

 in Beaver Brook Gulch. It was very fond of resting upon the rocks jut- 

 ting over the road leading up the mountain. As disturbed by persons 

 passing over the roacl, it would fly from rock to rock, and, when chased 

 for the distance of a few rods, would fly off' at a tangent, and return to 

 the rock from which it first started. 



A Stenojjogon, allied to, if not identical with, S.fasciatus Say, was quite 

 common upon sandy spots near Denver, and in Canon City upon the 

 banks of the Arkansas Eiver. The places on which it settled corre- 



