650 REPORT UNITED STATES GEOLOGICAL SURVEY. 



In August, 138-1, according to Mr. J, Boll, tliey invaded portions of 

 Switzerland. 



In Germany tbe records go back to 1333. In tliis year, and until 

 1336, they abounded. Entering? Hungary, they overflowed into Poland 

 and Austria. They then divided into two great swarms, one of which 

 flew southerly into Italy, the other into France, Suahia, Bavaria, Thn- 

 ringia, and Saxony. In Germany they again occurred in 1543. In 1G93 

 they invaded Thuringia, going from Hungary by way of Austria, 

 Schlesia, and Bohemia, and invading the region about Jena, Gotha, 

 Erluit, and Weimar. 



In Germany the locust years w-ere as follows: 1333-'36, 1475, 1527 

 and 1543, 1030, 1680, 1093 aiid 1090, 1712, 1714, 1715, 1719, 1727-'31, 1734, 

 1740- '50, 1752-'54, 1759, 1701, and for the present century, 18(>3, 1825-'30, 

 1850, 1859. In 1873-74 small numbers appeared in swarms about 

 Genshagen, near Berlin ; they laid their eggs, and in the middle of 

 June of 1875 the larviie appeared in millions, becoming fledged in July. 



Ko[)pen has published (Horre Soc. Ent. Eoss. iii, pp. 89-240) an elab- 

 orate memoir on the migratory locust of Southern Russia. lie gives, 

 in the iirst place, a biography of his subject, which includes several 

 memoirs published in Russian journals. With regard to the species 

 Koppeu remarks on the various opinions of entomologists as to the rela- 

 tion between Pachyfylus migratoriiis (Linn.) and P. cinerascens (Tab.), and 

 comes to the conclusion that the two supposed species are to be regarded 

 as varieties of one and the same, and that Edipoda tatralca (Motsch.) is 

 identical with P. cinerasceyis. The form which he met with most abun- 

 dantly in South Russia is the true P. onigraturius. 



The development of the insect is described by Koppen in detail. The 

 eggs are deposited by the females, to the number of GO to 100 together, 

 in little nests surrounded by a membranous envelope. The eggs are 

 laid in autumn and the young hatched in the following spring. The 

 envelope is burst a little while before the exclusion of the young. The 

 eggs display a great power of resistance to the influence of cold ; they 

 have been found to retain their vitality when the temperature reached 

 20° Fahrenheit when placed with earth in a large glass vessel. 



The larvfB are said by Koppen to moult four times, and the fourth 

 moult produces the winged insect. The different stages are described 

 by Koppen. At the end of May (1801), eggs taken from the ground 

 showed the eyes, antennae, segments, and legs of the larvae distinctly; 

 and a little while before hatching, the larva? could move witliin the egg. 

 On its emergence the larva is yellowish-white, with a rosy tinge; in 

 three to four hours its color is grayish black. Before and during each 

 moult the larvae are sluggish. At the final moult, which always takes 

 place in the hottest sunshine, the animals hang head downward, by the 

 hind feet, upon the stalks of grasses, &c. This enables the insects to 

 twist about in all directions, in order to free themselves from the skin. 

 The expansion of the wings occupies about twenty minutes after the 

 completion of the moult (twenty two minutes according to Ivoste, who 

 says that the moult itself occupies sixteen minutes); during this period 

 Koppen observed that a dark yellow fluid was distributed over the 

 wings in microscopic drops. The period which elapsed between the 

 arrival of the insect at the winged state and the deposition of tbe eggs 

 is uncertain ; the statements of different authors vary between four 

 weeks and two mouths. 



Ko[)pen describes the nearly indiscriminate voracity of these insects, 

 but remarks that certain plants appear to be avoided by them, namely, 

 flax and hemp, the Cucurbitacecv, and, according to Petzholdt, dwarf 



