Locust Ravages East of the Mississippi. 199 



ground with their eggs.* The following, which refers to 

 the same species, is also interesting : 



While the migrating hopper committed such devastation west of 

 us, we here at Bluffton have the manor-born, in immense numbers. 

 A patch of potatoes and some sweet corn seemed in danger of being 

 consumed, when a flock of purple grackles, our crow blackbird, as 

 it is usually called, came to our rescue. The few days that they have 

 visited the patch has thinned out the hoppers amazingly. I never 

 before noticed that this bird was so useful in this respect ; and as 

 they are plenty, we may expect to be rid of the big grey fellows 

 (hoppers). They are more than twice the size of the Colorado hop- 

 per, and are nearly as bad on a crop when plenty. What saved our 

 little crop from utter destruction was an open field of land thickly 

 covered with wild chamomile, upon which they fairly swarmed. 

 On this we saw them as thick as the Colorados, in Sedalia or War- 

 Tensburg.— [S. Miller, in Rural World, August 14, 1875. 



Though unusually common, yet differ entialis, if I may 

 judge from my own experience in our fields and around 

 Chicago, that year, compared only as one to fifty with 

 Atlanis, and it is doubtful if it formed a larger proportion 

 of the flights. How are these exceptional migrations of 

 local species to be explained ? We know, from what has 

 preceded, that they have occurred at intervals in the East, 

 and we now have evidence that they may occur in any 

 part of the country ; and indeed local swarms were not 

 confined to Illinois in 1875, as they were also noticed in 

 Kentucky. I think the explanation is simple. The ex- 

 cessively hot, dry years of 1873 and 1874 permitted the 

 undue multiplication of these native species, and they 

 were already very troublesome in the latter year, (ante, 

 p. 192). The myriads that hatched out in 1875 were 



* The eggs of Caloptenus differ entialis may be distinguished from those of 

 spretus by the larger and more irregular size of the mass ; by the greater num- 

 ber composing it ; by the somewhat larger size of the individual egg, which meas- 

 ures 0.19—0.22 inch in length ; by the coarser reticulations of the shell, and by the 

 brown color of the gummy fibrous matter that is intermixed with them and glues 

 tbem together. The color of the egg varies from yellow to deep carneous, the 

 latter prevailing, and the posterior or narrower end is always somewhat constricted 

 and darker. 



