2 BULLETIN 436, U. S. DEPARTMENT OF AGRICULTURE. 
DISTRIBUTION. 
So far as known, the distribution of this flea-beetle is confined to 
those areas of the southwestern United States that are normally 
semiarid in climate. As was stated in a preceding paragraph, the 
observations by the writer and his associates have been confined to 
California, Arizona, and New Mexico, and the species has been col- 
lected in practically all of the lower altitudes throughout these 
States. Collections in the higher altitudes show the species to be 
usually absent. This is no doubt due to the annual rainfall, which 
usually increases with the altitude. An exception to this rule, how- 
ever, was found by Mr. F. H. Gates, during the fall of 1915, when 
he took several of the adult beetles at Prescott, Ariz., elevation 
5,000 feet, where they were injuring Sudan grass. The writer, three 
months previous to this, had made observations throughout northern 
Arizona, stopping at Kirkland, Prescott, Ash Fork, Flagstaff, Hol- 
brook, Williams, and Joseph City, all of which are located at altitudes 
over 3,000 feet, and although a careful and prolonged search was 
made upon various known food plants, not a specimen was found 
and no injury was apparent except at Prescott, where typical feed- 
ing scars were found on corn. 
Through the kindness of Dr. F. H. Chittenden, the writer was per- 
mitted to make use of certain records in the files of his office and 
found that Prof. E. S. G. Titus had collected the species upon sugar 
beets at Lehi, Utah, and Huntington Beach, Cal.; that Mr. E. L. 
Crow found specimens at Yuma, Ariz.; and that Air. H. O. Marsh 
collected specimens feeding upon com at Anaheim, Cal.; the type 
specimens were secured at Los Angeles, Cal., and Dr. George H. Horn 
reported it as also occurring in Arizona. Only one other observation 
has apparently been recorded; 1 this was by Dr. A. W. Morrill, who 
mentions it as occurring upon Sudan grass at Phoenix, Ariz. 
ECONOMIC CONSIDERATIONS. 
To understand properly the nature of insect damage to crops 
growing on irrigated tracts in the southwestern semiarid regions of 
the United States one should know something of the existing condi- 
tions. A tract of land is often found, varying from 200 to 100,000 
acres or more, entirely surrounded by thousands of acres of land 
which is practically worthless from an agricultural standpoint; yet 
growing upon this land are weeds and grasses which serve as the 
native food plants for certain insects. When this comparatively 
small irrigated or dry-farm tract is planted to any crop, such as corn, 
milo maize, Kafir corn, etc., a great many of these insects quickly 
attack the new growing crops and feed upon them. Then, when 
1 Morrill, A. W. Report of the entomologist of the Arizona Commission of Agriculture and Horti- 
culture. Ariz. Com. Agr. Hort,, 6th Ann. Rpt, p. 33, 1914. 
