472 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



be mainly, however, a compilation, writes as follows regarding the 

 European locust : 



That copulation can be accomplished very soon after emerging from the last larva- 

 skin (he does not name a pupa stage), is shown by the fact that one occasionally finds 

 individuals engaged in the act while the wings are still tender and have not attained 

 their full color. But the act is as a rule performed in the course of several days (after 

 becoming winged), or even after a still longer period. 



The male lets the female free in the course of twelve to twenty minutes, after which 

 the female before proceeding to lay, employs herself in feeding again for several days. 

 As soon as her eggs are ripe, which, according to Kosten, requires seven days on the 

 •average, she seeks a satisfactory spot to deposit them. (He then describes the act of 

 laying, which is much as in C. spreius.) The eggs are generally found at a depth of 4 

 •centimeters, or more, below the surface. In this act, requiring considerable time, she 

 by no means rids herself of her whole stock of eggs at once, but may pass several weeks 

 even in perfecting them. Possibly for a second or third deposit of the egg-mass a re- 

 newal of copulation is necessary. At least such a repetition has been noticed in the 

 •case of females that had already been found laying, and has always been followed by 

 -a new deposit of eggs. In all cases, whether after a single or repeated coupling, which 

 latter may depend upon the relative number of males, and the temperature of the 

 iseason, a division is made of the egg-stock into several deposits as is shown by the fact 

 that the larger egg-pods seldom contain more than one-half, and the smaller very gen- 

 erally a much smaller fraction of the whole mass of eggs produced by one female, 

 which mass may amount to one hundred and fifty or more. With the last deposit the 

 female has accomplished her destiny, so that she not seldom remains dead on the spot 

 ■where the laying occurred. On the other hand the males even after repeated coupling, 

 and with several females, appear to be able to prolong their life, and may be found 

 ■alive as late as October. 



From the comparatively long time during which the winged locusts may be found, 

 extending very commonly from the end of July to the end of September, it must not 

 be at once concluded that the life of an individual is correspondingly long. 



In:selecting a spot for the perfection of this egg (packet) dryness is of the first im- 

 portance to the female, and besides this a certain degree of hardness, They prefer 

 loamy and clayey ground to pure sand. Besides this, a spot is naturally selected which 

 offers suitable and plentiful food to the hatching brood. 



Fallow fields lying alongside cultivated fields and meadows appear to present an 

 unusual attraction to the female when ready to lay. That the eggs, as such, winter 

 over under the surface can be set down as a matter of common observation. The 

 young brood generally do n'ot hatch before the end of April. 



The geographical distribution of the migratory locust of Europe and 

 Asia (Fachytylus migratorius) has been discussed by Herr F. T. Koppen 

 in Petermann's ^'Mittheilungen aus Justus Perthes' Geographischer An- 

 stalt" (1871, p. 361), his paper being accompanied by a map showing 

 the range of the insect. We translate an abstract of it by M. Preud- 

 homme de Borre, in the Oomptes Eendus of the Entomological Society 

 of Belgium, 1871-72, p. xviii : 



The migratory locust is an Orthopter peculiar to the torrid zone and a large part of 

 the north temperate zone of the Old World ; but, in this last region, its northern limits 

 is subject to some variations, the explanation of which is one of the principal objects 

 of the work of M. Koppen. 



In countries such as those of Arabia and Persia, where the mean temperature of the 

 year, as that of the different seasons, is almost invariable, the abundance of the species 

 in question does not vary; it is normally limited, both by the quantity of its nourish- 

 aneut and the natural enemies of tk© insect. But this is not the case /.n those countries 



