DEGENERATION OF THE SPECIES IN TEMPORARY REGION. 245 



duce but one generation annually and whose active existence is bounded 

 by the spring and autumn frosts, the duration of active life is propor- 

 tioned to the length of the growing season."- 



Hatching late and coming to maturity in July and August, in its na- 

 tive haunts, the species, when born in the southeast country, is in the 

 condition of a subalj)ine or boreal annual plant grown in a southern cli- 

 mate. Such a plant will rarely hold its own in the changed climate. 

 If it lives at all, it grows more rankly, blossoms prematurely, and 

 deteriorates. For want of the proper ripening influence of autumn, 

 the seeds either fail to mature, or, if they mature, they germinate out 

 of season, and the plant perishes in the second generation. Our locust 

 must and does deteriorate under the same circumstances, and the 

 power of migrating back to a congenial climate alone saves it from per- 

 ishing. 



Had the insects which hatched in Texas, Missouri, Kansas, &c., in 

 1875 or 1877 remained there to propagate, their eggs would all have 

 prematurely hatched the same season : the young would have been still 

 more feeble than their parents which hatched in spring, and would 

 most of them have perished before they had had time to procreate and 

 provide for the continuance of the species. It has often occurred to us 

 that the species might, in the Temporary region, become profoundly 

 modified in the course of two or three generations in the direction of 

 atlanis ; and that in this way and through miscegenation with allied 

 indigenous species its extinction from said region might to some extent 

 be accounted for ; but the evidence is against this supposition, and 

 such influences play a very unimportant part, if any, and should not be 

 considered factors in the problem. All that can leave do so, and those 

 which do not, eventually perish. The fact of deterioration, debility, 

 and disease in our Rocky Mountain locust when in the southeast 

 country is very generally recognized by farmers, while all close ob- 

 servers recognize it. The following opinions of well known naturalists 

 in the locust region may go on record in this connection : 



Mr. Riley is of the opinion that the grasshoppers run out in a few generations after 

 they leave their native sandy and gravelly soil. My experiments, so far as they go, 

 verify that opinion. For several years I have caught grasshoppers during early sum- 

 mer that came fresh from the direction of the mountains, and by attaching their legs 

 with fine silk threads to a small spring-balance, found that their physical strength was 

 twenty-five to fifty per cent, greater than that of grasshoppers treated the same way 

 that were hatched in Nebraska or in States farther eastward or northward. The same 

 result was reached by caging them and ascertaining how long they would live without 

 food and also by vivisection. In some places, also, the eggs that were laid in different 

 years since 1864 did not hatch out. The changes from extreme wet to dry and from 

 cold to hot weather, or some other unknown causes, seem to sap their constitutional 

 vigor. Were it not for this, long ere now these grasshoppers would, from their enor- 

 mous numbers, have desolated the whole country as far east as the Atlantic. — (Prof. 

 Samuel Aughey, of the University of Nebraska, in the Lincoln (Nebr.) Journal.) 



I have observed hundreds of winged locusts fall to the ground during flight, either 

 already dead or soon dying. These, upon examination, have generally proved to con- 



