44 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no 



Distribution: Figure 14 shows the distribution of devastator as 

 known to the authors. However, uncertainty concerning identifica- 

 tions in the group during the past has been responsible for early 

 published records which pointed to a much wider distribution. Both 

 Essig (1926, p. 81) and Harper (1952) include Arizona in the dis- 

 tribution, but Hebard (1935b, p. 304) stated that devastator does not 

 occur there. Buckell (1922, p. 31) included devastator in his British 

 Columbia list, based on a Vancouver Island record by Caudeil. 

 Caudell (1908, p. 77) recorded devastator conspicuus from Wellington, 

 British Columbia, and a manuscript note written by him in 1926 

 indicated that the record was based on a female specimen. The 

 specimen, a female with red hind tibiae, is in the U. S. National 

 Museum, and is bilituratus bilituratus. 



Male specimens of Melanoplus devastator have been examined from 

 the localities shown in figure 14. 



Biology and economic importance: When Scudder (1878b) 

 originally described devastator, he stated that it probably "is the 

 source of most of the damage to crops in California," and it frequently 

 has been of much importance there. The fullest early account is 

 Coquillett's (1892) report on the 1891 infestation, which includes 

 biological notes. Woodworth (1902) stated that devastator was one 

 of the two most destructive California grasshoppers in 1901. Brief 

 later accounts are by Essig (1926) and Harper (1952). Fulton (1930, 

 p. 634) referred to devastator as one of the "more strictly prairie species" 

 of the Willamette Valley of western Oregon and universally present 

 there during the proper season. 



A concise summary of the biology and economic importance of 

 devastator by Wilson (1947) points out that it is the dominant species 

 on much of the scmiarid range in California, and that preventing mass 

 migrations from natural habitats to cultivated crops is one of the 

 critical control measures, in addition to preventing serious damage to 

 range forage. Nymphs inhabit much of the range and feed on legumes, 

 alfilarias, bromes, and hordeums, in the order named, as long as they 

 remain succulent. Wilson, to whose excellent summary the reader is 

 referred for more detailed information on habits and seasonal occur- 

 rence, commented as follows on the physiological distinctness of 

 devastator: 



By the second week of July the species has largely reached the adult stage. To 

 the casual observer the adults resemble the lesser migratory grasshopper (M. 

 mexicanus Sauss.). However, field and microscopic observations show that these 

 two species differ in external anatomy, habitat, and seasonal history. M. devasta- 

 tor is naturally found on the range, whereas M. mexicanus is found in California 

 and Nevada, largely, if not entirely, in irrigated alfalfa fields. Dissections have 

 shown that, unlike M. mexicanus and many of the other economic species that 

 begin oviposition within 10 days after reaching the adult stage, M. devastator has a 



