THE NEW MEXICO KANGE CATERPILLAR. 



79 



moving at all. Only one or two of the most vigorous reached the 

 shade, and these died immediately when returned to the sunlight. 



These repeated experiments proved conclusively 

 that the universal habit of the species of seeking a 

 position on a weed or grass stem, above the sur- 

 face of the ground and if possible on the shady side 

 of the stem (see fig. 43) , has been adopted as a means 

 of self-preservation. 



FOOD HABITS AND FOOD PLANTS. 



The habit of ascending any plant that will raise 

 the larvae of the Hemileuca from the heated surface 

 of the ground has given the species the reputation 

 of feeding on alfalfa, cereals, and weeds of various 

 sorts. It can be safely asserted that they eat noth- 

 ing but grass, and only the native grasses. Indi- 

 viduals were at different times placed upon timothy, 

 bluegrass, and various grains, wheat, oats, and bar- 

 ley, but they refused them entirely. 



The caterpillars feed on most of the native grasses 

 that are found in northeastern New Mexico, the 

 Bouteloua group being their first choice. The 

 list given below was prepared by gathering sam- 

 ples of the grasses on which these pests were 

 actually feeding, and, in cases of doubt, sending 

 this material to the Department of Agriculture in 

 Washington for determination. The list is by no means complete, 

 but comprises the main food plants of the species. 



Fig. 43.— The New Mex- 

 ico range caterpillar: 

 Larvee clustered on 

 weed stem, to avoid 

 the heated surface of 

 the ground. (Orig- 

 inal.) 



List of food grasses of the range caterpillar, Hemileuca olivix. 



Hairy mesquite grass (Bouteloua hirsuta). 



Grama grass (B. oligostachya) . 



Racemed Bouteloua (Atheropogon curti- 



pendula) . 

 Buffalo grass (Buchloe dactyloides) . 

 Hair-grass dropseed (Sporobolus airoides). 

 Hilaria cenchroides. 



Hall's beard-grass (Andropogon hallii). 



Texan timothy (Lycurus phleoides). 



Marsh spike-grass (Distichlis spicata) . 



Sitanium jubatum. 



Blue-joint (Agropyron smithii). 



Hordeum cxspitosum. 



Brome-grass (Bromus polyanthus). 



THE PUPJE. 



PUPATION. 



The caterpillar when full grown becomes exceedingly sluggish in 

 its movements, and for a day or two hangs inert from a weed stem 

 or travels slowly about looking for a convenient retreat in which to 

 transform to the pupal state. The color } chiefly yellow during the 



