THE NEW MEXICO RANGE CATERPILLAR. 63 



observed outside this limited area in New Mexico and the very similar 

 adjacent borders of Oklahoma and Texas; whether or not the species 

 can exist beyond this region is yet to be seen. 



It seems probable that altitude may indirectly exert'some influence 

 on the distribution of this species of Hemileuca. In other words, 

 below a certain altitude, under the peculiar climatic conditions that 

 prevail in New Mexico and similar semiarid regions, the intense heat 

 of the midday sun may prove fatal to the younger larva) unless the 

 character of the native vegetation affords the necessary shelter. 

 Farther north, if the species follows the grama-grass range in that 

 direction, as it seems to be doing at present, the chief danger to the 

 insect may be the possibility of continued stormy or unfavorable 

 weather during the egg-laying period in the fall. 



THE SPECIFIC IDENTITY OF THE INSECT CONCERNED. 



Specimens of this species were described by Professor Cockerell 

 some twelve years ago as Hemileuca sororia, race 1 oliviae. The type, 

 a male, came from Santa Fe, X. Mex., and is now in the United 

 States National Museum. The species sororia, of which olivise was 

 described as a race, was originally characterized by the late Henry 

 Edwards from a single female from La Paz, Lower California. Noth- 

 ing further is known of this form, except that Hemileuca Jiualapai 

 Neumoegen, described from a single female from southern Arizona, 

 has been referred to it as a variety. Nothing further is known of 

 Jiualapai either, but in the light of the present situation it appears 

 unlikely that these forms are races of one species, but rather separate 

 species, and it has been thought best to here designate the species 

 with which we are at present concerned as Hemileuca oliviae Cockerell. 



Beside the forms just cited, a number of closely allied species have 

 been described from Mexico. Twelve species altogether are at present 

 known which are closely allied to olivia . as follows: 



Hemileuca rubridorsa Felder. 



Felder'a description lb without definite locality; his figure represents a female. A 

 male specimen, undoubtedly of this Bpecies, has been received from Mr. Roberto 



Mtiller, from Mexico City, which enables us to locale the species as an inhabitant of 

 the Mexican plateau. 



Hemileuca norba DrUce. 



Described from Amecameca, State of Morelos, Mexico, from the same general region 

 as the foregoing. The type specimen, a male, is before us, but no additional material. 



Hemileuca minette Dyar. 



This form is probably from the vicinity of Mexico City, although the single type is 



without exact locality. The three species may possibly be but variations of one spe- 

 cies, but from the present scanty material they seem distinct, and must be considered 

 so until proven otherwise. 



