40 PROCEEDINGS OF THE NATIONAL MUSEUM voL.no 



(Icf); Tempe, swept from alfalfa, June 8, 1950, N. J. Nerney (19); 

 Theba, on alfalfa, Oct. 26, 1939, O. L. Barnes (Icf); Tumacacori 

 National Monument (Pendleton Ranch), Sept. 9, 1939, E. R. Tinkham 

 (1 c^) ; Yuma, alfalfa, Aug. 2, 1938, O. L. Barnes (19) ; Yuma, alfalfa, 

 Nov. 11, 1936, O. L. Barnes (19). 



Of 311 specimens of hilituratus defectus examined, only two (one 

 each from Las Vegas, N. Mex., and Lupton, Ariz.) have glaucous 

 hind tibiae; the others are red. However, 13 of 57 specimens which 

 are intermediate with hilituratus hilituratus have glaucous hind tibiae. 

 None of these intermediate specimens is as long-winged and large as 

 the most optimum specimens of hilituratus defectus. Several of the 

 intermediates from southern Colorado and northern New Mexico are 

 noticeably small and dark. 



The distribution of males of hilituratus defectus examined is shown in 

 figure 6. The single Texas locality is Phantom Lake, Davis Moun- 

 tains. 



Biology and economic importance: This grasshopper is important 

 economically and is most injurious in irrigated areas (Ball, Tinkham, 

 et al., 1942; Harper, 1952). It is said by Harper not to have become 

 a pest in the Imperial Valley of California until 1915 when farming 

 there became extensive. Cultivated crops are injured more severely 

 than grazing areas. 



Barnes (1955) compared five plants as food for hilituratus defectus 

 in cage studies in Arizona, and his paper should be consulted for 

 observations on mating, egg development, adult body dimensions, 

 and weights of adults, as influenced by diet. Two annual generations 

 usually are reported, and Barnes feels that a considerable difference 

 in average size of individuals representing the two generations probably 

 is due to the plants available as food. For instance, in 1944 the second 

 generation in the Yuma, Ariz., area developed almost exclusively on 

 dry alfalfa and Bermuda grass, and resulting adults were much smaller 

 than first generation adults. A comparable difference in adult size 

 at the San Carlos Indian Reservation, Ariz., was noted in the two 

 generations in 1953. First generation nymphal diet consisted mainly 

 of forbs, while the second generation had to develop mostly on grasses. 

 It may be significant that all of the especially long- winged specimens 

 discussed in detail, which bear habitat data, were associated with 

 alfalfa. 



In southern California (Harper, 1952), hilituratus defectus first 

 hatches by March or early April; then the second generation occurs 

 in September and October. Some early and late dates on labels of 

 adults examined are as follows: Yuma, Ariz., Jan. 5, 1937; Bard, 

 Calif., Jan. 19, 1937; Yuma, Calif., Apr. 17, 1942; Saugus, Calif., 

 Oct. 19, 1950; Zion National Park, Utah, June 18, 1953; same, Sept. 



