652 REPORT UNITED STATES GEOLOGICAL SURVEY. 



stateraentH of autbors are at variance. The observations of S.ydon and 

 Donzingk give about a quarter of a German mile {i. e., about 0.975 mile 

 English) in tbe hour. Teehemewsky asserts that they only advance 

 about 350 feet in the day upon grass land. 



or the senses of tbe locust, Koppen seems to regard hearing as tbe 

 sharpest. The senses of smell and taste are exerted in the selection of 

 food ; and that of touch is displayed in the sensibility of the insects to 

 changes of weather, especially temperature. Sociability is regarded by 

 the author as characteristic of the locusts. The larvjTe proceeding from 

 one nest seem to keep togetber lor a time ; they alterward associate in 

 larger masses vvbicb move togetber in search of nourishment. These 

 migrations in mass commence in the second stage of larval life, but be- 

 come more general after tbe second moult. The migration usually takes 

 place in the morning and evening, Tbe author remarks ni)on tlie direc- 

 tion of the migrations of these insects, which be regards as intluenced 

 to a certain extent by an instinctive perception of tbe direction in whicb 

 abundant food or a suitable breeding place is to be found, but uioditied 

 or even sometimes caused by external agents, especially the winds. 

 The autbor also discusses the primary causes of tbe great migrations 

 of these insects and tbe phenomena observed during their flight. 



In the south of Russia tbe batching of the eggs takes place, according, 

 to tbe weather, at the end of April or beginning of May. A few larvre 

 are sometiu)es produced on warm days in October, but these soon die. 

 The batching occupies from two to three weeks, according to circum- 

 stances. The winged insects appear in the beginning and middle of 

 July; copulation takes place early in August; and theoviposition ex- 

 tends from the middle of August to October. The dry steppes con- 

 stitute tbe chief haunt of tbe locusts; damp places they seem to avoid. 

 The females prefer for the reception of their ova the solid virgin soil, 

 and rarely visit 5)lougbed land for this purpose. Damp and cold are 

 unfavorable for tbe develoi)ment of the eggs. The autbor discusses iu 

 great detail the external conditions which act favorably or unfavorably 

 upon these insects. The greater part of this section is devoted to tbe 

 consideration of tbeir enemies, of which Koppen gives a formidable 

 list (pp. 151-lGG). 



Leime and other authors have given Tartary as tbe true home of the 

 migrating locusts; but iu Tartary no large swarms occur. In tbe 

 author's opinion, the countries in which the swarms are seen are also 

 tbe countries of tbeir birth. He cites many facts in support of this 

 opinion, and in illustration of tbe geographical distribution of the in- 

 sect, the northern limit of their migratory or nomadic life being a line 

 passing from Spain through tbe south of France, Switzerland, Pomera- 

 nia, South Russia, and South Siberia, to tbe north of China. To tbe 

 north of this line tbe insects generally occur only singly. Many inter- 

 esting details as to tbeir occurrence iu vast numbers are given by the 

 autbor (pp. 190-205). 



Kiippeu also describes tbe injury done by the locusts when they occur 

 iu great numbers, and indicates tbe means adopted for tbeir suppres- 

 sion (pp. 205-240). 



Koppen also notices CaJoptemis itaUcus, a congener of our C. spretus, 

 which likewise oc;curs in South Russia, and at such times, as in other 

 regions of Southern Europe, sometimes in injurious numbers. Other 

 species which are also occasional devastators, especially when asso- 

 ciated with tbe migratory species, are Pachytxjlus stridulus, (Edipoda 

 vastator, SStauronotns vastator, S. cruciatus, and Fezotettix alpina. 



