302 THE ENTOMOLOGIST. 



represented by a few species, Polyphylla 10-lineata, Say, of 

 which elytra only were found, Trirhahda, sp. indet., Epicauta 

 maculata, Say, and Graptodera foliacea, which occurred in some 

 numbers on Cucurhita perennis, Gray. 



Besides the above, there was also a most interesting little 

 colony of insects, supported entirely by the cottonwood-trees 

 {Populus halsamifera var. candicans) , numbering six species. 

 First, a magnificent Smerinthus, apparently S. occidentalis, Hy. 

 Edw., larger than any of the British species, with beautifully 

 madder-pink hind wings, — this I found at rest on a cotton-wood 

 branch ; secondly, a Catocala, not unlike the European nuptu, 

 which I saw but failed to catch, and also found the empty pupa- 

 shells, with the usual bloom on them, under the bark of the 

 trees. Then there was a Cossus boring in the living trees. 

 I obtained a young larva, and in a dead stump were also borings, 

 which proved to be those of a species of Sirex or Urocerus. 

 I should never have supposed there was anything else than 

 Cossus in that dead stump, were it not that some ichneumons, 

 the like of which I had never seen before (except a single ex- 

 ample flying, which I did not catch, but feel sure was the same, 

 by Red Creek, in Custer Co.), with exceedingly long ovopositors, 

 evidently laying their eggs in some larvae within the stump. So 

 I bottled these great yellow ichneumons, as well as a male 

 I found flying round belonging to the same species, and cut open 

 the stump with an axe, which led to the discovery of the 

 JJrocerus. Since then I have sent this and the ichneumon to 

 Prof. C. V. Riley, who tells me that the latter is Thalessa lunator. 

 Lastly, there were extensive webs of an Arctiid larva on the 

 branches of the cotton-woods, apparently the same species as 

 that which does much damage to Populus angustifolia in the 

 Hardscrabble district of Custer Co., and was observed in Pleasant 

 Valley, Fremont Co. The larvae resemble in many ways those 

 of Hyphantria cunea, which is reckoned so great a pest in the 

 Eastern states, but I sent specimens to Prof. Riley in spirit, and 

 he could not identify them. 



The next camp was some twelve miles away, also in Pueblo 

 Co., and at a higher elevation, whence we could see the 

 open prairie stretching out to a level horizon in the east, and 

 looking like the sea. Some dark vegetation marked the course 

 of the Arkansas river, and on it, some thirty miles away, lay the 



