8 



fourth grown to have fotiud their wny to the Buhach plantation from 

 the foot-hills, M distance of from 15 to 20 miles. 



When I first arrived in the valley, the Devastating and Ash-colored 

 Locusts were most numerous in those grain fields that had not been 

 plowed for a year or more, that is, in fields of what is commonly called 

 "volunteer" grain, i. e., self-seeded. Some of the locusts remained in 

 these fields for two weeks after the grain had been harvested ; by the 

 latter part of July scarcely a single specimen of either the Devastating 

 Locust or the Ash-colored Locust could be found in these fields, but the 

 low waste places, which were quite numerous in and near all of the grain 

 fields, and which were covered with a rank growth of green weeds, were 

 infested with immense numbers of these locusts, which doubtless will 

 breed in these situations. 



These waste places are covered with water during the latter part of 

 the winter season, and sometimes until late in the summer. When the 

 proper time for putting in the seed arrives they are too wet to be plowed 

 and seeded, and are therefore allowed to remain undisturbed from year 

 to year. The green weeds which these waste places contain late in the 

 season, when the surrounding fields contain nothing green, furnish food 

 to the locusts until their egg- laying season arrive?, when they will doubt- 

 less deposit their eggs in these waste places; and as these eggs do not 

 hatch until the following spring, they must be covered with water for a 

 period of two or three months. This would not necessarily destroy their 

 vitality unless they were covered by the water for too long a time, since 

 Professor Eiley has ascertained that the eggs of the Eocky Mountain 

 Locust (Galoptenus spretus, Uhler) were not affected by being submerged 

 in water for three months during the winter and early spring.* 



I 



CAUSE OF THE ABUNDANCE OF THE DEVASTATING LOCUST IN THE 

 SAN JOAQUIN VALLEY DURING THE SUMMER OF 1885. 



If, as we have supposed above and have every reason to believe to be 

 a fact, the Devastating Locusts deposit their eggs in these waste places, 

 we see that in ordinary seasons these locusts will not appear in suffi- 

 cient numbers to attract attention, since the water will be removed, by 

 evaporation or otherwise, from the more elevated portions of these 

 waste places first, and therefore the eggs which have been deposited 

 in those elevated places will be the first to hatch out, followed by those 

 that had been deposited in less elevated places, and so on. It follows 

 that those hatched out the earliest will be the first to acquire wings and 

 migrate to the adjacent fields, followed after a certain time by those 

 hatched out next, and so on. By coming into the fields so gradually 

 and spreading over so large an area of land, their presence will scarcely 

 be noticed. It is also quite certain that many of the eggs are destroyed 

 by being too long covered by the water, since, in ordinary seasons, sev- 

 eral of these waste places contain water until quite late in the summer. 

 Thus it happens that in ordinary seasons the locusts never appear in 

 sufficient numbers to attract attention. 



. Last winter, however, but little rain fell, and, as a natural conse- 

 quence, what little water was collected in the waste places soon evap : 

 orated, leaving these places perfectly dry for some time before the time 

 for the locust eggs to hatch out had arrived; consequently, when the 

 time for these eggs to hatch out did arrive, they all hatched out within 

 a short time of each other, and as they would ail acquire wings and mi- 



* See the First Annual Report of the U. S. Entomological Commission, pp. 359, 360. 



