yet seldom implemented. Adultgrasshoppers andlargernymphs arecommonly used for density estimates and prognoses of future damage, especially to rangeland. Numbers or sizes of egg pods are rarely used for this purpose because sain- pling this underground stage is difficult, time-consum- ing, and requires special equipment-, also, the taxonomy of grasshopper egg masses would have to be determined. The ideal sampling method would be inexpensive and quick, offering the observer accurate estimates of both nymphs and adults of whatever grasshopper species happened to be in the vicinity. Unfortunately, research- ers interested in developing such a method run into a variety of obstacles. Collection records such as those presented in this manual indicate that numerous species of grasshoppers are likely to occur in any given part of the state. Field observations of various species indicate considerable differences in mobility and wariness, both among species and development stages. Prevailing weather conditions have been previously mentioned as sources of error for grasshopper counts. Foliage type, density, and height are also confounding factors (see Southwood, 1978 for a review). Finally, there can be considerable variability among human observers with respect to following instructions, efficiency, and accu- racy of observations. Thus, no ideal sampling technique has been devel- oped. Further, it appears that ease of use and time necessary to do the work are inversely related to accu- racy and precision of the population estimate (Tbomp- son, 1987). Grasshopperdensitiesaregenerallypresentedasnum- bers of all species (lumped) per square yard (most common estimate), per square meter, or per square foot. The technique most commonly used for these estimates requires the surveyor to count the number of grasshop- pers fleeing a visually estimated one-square-foot area approximately 10-15 feet ahead (USDA, undated). The surveyor repeats this procedure 18 times per sample location, adds the 18 observations, and divides by two to determine the numbers of grasshoppers per square yard. Although this technique remains in com- mon use, its inaccuracy and inconsistency has been well documented (Onsager, 1977). More accurate density estimates can be obtained by placing square-foot or square-yard hoops on rangeland prior to conducting the actual counts (Richards and Waloff, 1954-, Onsager and Henry, 1977). Unfortu- nately, the price of accuracy requires at least twice as much travel, time, and labor to produce data because study sites must be visited twice: once to set the devices and again to pick them up and collect data; consequently, this procedure is used infrequently and primarily for research applications. Techniques developed for special research projects requiring even more accurate estima- tionofgrasshopperdensities includequicktraps (Turnbull and Nichols, 1966), night cages (Anderson and Wright, 1952), drop cages (Hills, 1933), and net samplers (Smalley, 1960). Various methods have been attempted to determine grasshopper species composition. If density and popula- tion diversity are relatively low, ft field surveyor who uses the 18-station walking count method may be able to identify some key species as they jump away (Joern and Pruess, 1986; Pfadt, 1982, 1984). Sweep-net sampling may be the most widely used alternative for this purpose. Its advantage is that specimens can be preserved for identification under more controlled conditions or for further study by experts; the disadvantage is that some species may be abundant at a site but are rarely, if ever, captured, inthe sweep net. Capinera and Sechrist (1982a) described a "flush-capture" technique that would im- prove on the sweep-net technique because variance would be controlled. However, like the more accurate estimators of density, the "flush-capture" technique has logistical drawbacks. Because operating resources are limited in New Mexico, standard sampling procedures for grasshoppers have employed the 18-station walking technique de- scribed above (USDA, undated) with subsequent plot- ting of survey results (grasshoppers/square yard) on detailed county or regional maps. Estimates of grass- hopper densities in New Mexico are routinely made after most economic species have hatched (early sum- mer) and again after most of the same species are adults (early fall). This is a cooperative survey among person- nel of the U.S. Department of Agriculture and the New Mexico Department of Agriculture. For the nymph survey in parficular, initial survey locations may be 5-10 or more miles apart, depending upon the terrain, purposes of the survey, grasshopper densities, and signs of damage by these pests. Results of the nymph survey, grasshopperdamage estimates, grass- hopper identifications, development stages, range con- ditions, and current and long-range weather forecasts are all considered when a grasshopper control program may be initiated in the near future. Time is usually of the essence; if nymphal surveys suggest the possibility of a control program, survey personnel from state and fed- er,W agencies remain in close contact with each other and with affected landowners. Field experiments (Onsager, 1978) and modeling trials (Hardman and Mukerji, 1982; Onsager, 1984) strongly suggest that treatments provide maximum prevention of forage destruction if applied when most grasshoppers in an infestation are in the 3rd or 4th nymphal instar, relatively early in the year. Results of the adult survey are used to predict areas where economically significant populations (8 or more grasshoppers per square yard) may produce high nurn- bers of nymphs the following year. Adult grasshoppers