THE COLORADO BEETLE. 87 



myself. The variety (white with two of the lines united, 

 probably the species juncta) I found on the Arkansas." 

 (Journal Academy of Natural Sciences, Phila., iii, 1824.) 

 This would indicate that its natural habitat was the plains of 

 Dakota, Western Nebraska and Kansas, Colorado, and, per- 

 haps, the western portion of Indian Territory and Texas. 

 Dr. G. H. liorn, the well-known coleopterist, writes me as 

 follows: "West of the Mississippi I have it from Texas. I 

 have never seen it from Mexico nor west of the Rocky Moun- 

 tains. If it goes west, I believe it will be through New Mexico 

 and Arizona, and not over the Rocky Mountains." Probably, 

 coextensive with the original distribution of the Colorado 

 potato-beetle, is that of its original food-plant, a wild spe- 

 cies of Solatium, concerning which Mr. Sereno Watson, the 

 botanist of the U. S. Geological Survey of the 100th Parallel, 

 thus writes me : "The Solatium rostratum ranges from Texas 

 and New Mexico to the Upper Missouri eastward of the 

 mountains. I have no evidence of its being found at all west 

 of the Rocky Mountains, and, indeed, the order appears to 

 be almost wholly wanting throughout the entire Great Basin." 



In going to Colorado in 1875, while attached to Prof. F. 

 V. Hayden's Geological Survey of the Territories, I first met 

 with this beetle at Lawrence, Kansas, where Prof. F. H. 

 Snow told me it was chiefly confined to the Solatium rostra- 

 tum, a roadside weed which is now very abundant in Kansas, 

 and draws off the beetle from the potato, which consequently 

 suffers comparatively little from its attacks in that State. 



The question arises whether the cultivation of this weed 

 around potato fields in the East may not be a means of relief 

 from its attacks, though it might breed in still larger numbers, 

 if that were possible. 



In Colorado, I first noticed the beetle in the vicinity of 

 Denver, where it was not then common, but earlier in the 

 season had ravaged potato fields out of town. At Golden, 

 July 3, it was observed in abundance on Solatium rostratum; 

 not only the eggs, but the larvpe in all stages as well as the 

 beetles. I was told by one farmer that he had two rows of 

 potatoes devoured by them earlier in the season. Near Den- 

 ver, the potatoes had been injured by them early in the season, 

 and they had been abundant locally at Howardsville. It is 



