NATURE 



[May 7, 1891 



By far the greater bulk of the enormous collection 

 with which the author has had to deal was obtained 

 from the Florissant basin ; and it is to these alone that 

 our few remaining observations will refer. The mass of 

 material from these deposits is, however, so vast that in 

 the present volume (large as it is) the author has found it 

 possible to deal only with the Arachnids, Myriopods, and 

 the Neuroptera, Hemiptera, and Orthoptera among the 

 true insects. Some introductory remarks are, however, 

 given as to the relative proportions in which the Lepido- 

 ptera, Hymenoptera, Diptera, and Coleoptera, are repre- 

 sented in these beds. 



The total number of specimens of insects obtained 

 from Florissant during the labours of a single summer is 

 estimated to be more than double that obtained during 

 thirty years at the celebrated European locality, (Eningen.i 

 A remarkable difference occurs between the relative 

 number of species of the different orders of insects 

 found at the two places. Thus, while at CEningen the 

 Diptera are less than 7 and the Hymenoptera less j 

 than 14 per cent, of the whole ; at Florissant they reach | 

 respectively 30 and 40 per cent. On thi other hand, j 

 while the CEningen Coleoptera form nearly half of the ' 

 whole number, at Florissant they fall to 13 per cent. The j 

 great percentage of Hymenoptera is due to the prodigious 

 number of ants ; in which respect, as also in the small 

 proportion of beetles, the fauna agrees better with that I 

 of Radaboj, in Croatia, to which it likewise approximates 

 more closely in age. It would take too much space to 

 enter into the details of the proportions in which the 

 various families of the different orders are represented in 

 these be ds ; but it appears that, with the exception of 

 the Lepidoptera, nearly every prevalent family may be 

 demonstrated to have been in existence at that epoch. 

 Among the beetles, about three-fifths belong to the 

 normal series, and the remaining two-fifths to the 

 weevils ; water-beetles being unexpectedly scarce. Lepi- 

 doptera are rare, only eight species of butterflies, all 

 referable to different and extinct genera, and about the 

 same number of moths being at present known. It is of 

 especial interest to note that, while seven of the eight 

 butterflies belong to the Nymphalidce, no less than two 

 of these are referable to the sub-family LibytheincB, the 

 members of which, although found in every quarter of the 

 globe, are fewer in number than many other groups, con- 

 sisting only of ten species, referable to the single genus 

 Libythea. It is, therefore, a legitimate inference that 

 the Libytheince have been on the wane since the Oligo- 

 cene or some later Tertiary epoch. Some writers, it may 

 be mentioned, regard Libythea as the representative of a 

 family rather than a sub-family. 



In taking leave of the author, we congratulate him on 

 the patience and perseverance which have carried him 

 thus far through a task of unusual magnitude and diffi- 

 culty, and hope ere long to have the pleasure of welcoming 

 its completion. With the widely-scattered literature of 

 palaeontology ever increasing, the importance and value 

 of monographs like the present, where the whole subject 

 is collectively treated by a master-hand, cannot be too 

 highly estimated. R. Lydekker. 



•CEningen is situated on the right bank of the Rhin3, between Shaflfhausen 

 and Constance, and is in Baden, and not, as the author states on p. 26, in 

 Bavana. 



NO. I I 23, VOL. 44] 



5 TA TISTICS OF POP ULA TION AND DISEASE. 

 Studies, in Statistics. By George Blundell Longstaff. 



(London : Edward Stanford, 1891.) 

 <« Q^TUDIES" is a title appropriate to these somewhat 



^ detached investigations concerning at least three 

 different classes of subject. The first few chapters, relat- 

 ing to vital statistics, are described by the author as " of 

 an introductory and elementary character"; though the 

 discussion which is contained in one of them, on the 

 fluctuation of death-rates, varying according to the cause 

 of death, does not appear to us so very rudimentary. 



A great part of the book is occupied with the " growth 

 of population " : whether by " natural increase " or immi- 

 gration. England and Wales alone add 1000 a day to 

 the population of the world. " Over and above reserve 

 men who fill up the gaps caused by death, a fresh regi- 

 ment at full war strength daily marches to the front." 

 To what quarters are they marching? The answer in- 

 volves a consideration of intra-migration, as Mr. Long- 

 staff terms the migration between the several divisions 

 of the same kingdom. The inquiry brings into view the 

 relatively slow increase of rural as compared with urban 

 districts — a contrast not peculiar to the United Kingdom. 



These and other facts, extracted from records acces- 

 sible to all, are not absolutely new to the student of 

 Statistics. Yet they excite gratitude, almost as much as 

 if they were wholly due to the author ; enhanced as they 

 are by the wealth of his inferences and the luxury of his 

 illustrations. 



The statistics of the growth of America are less familiar 

 to the English reader. By a careful analysis of the Ame- 

 rican census, Mr. Longstaffestimatesthat nearly one-third 

 of the whole population (almost 28 per cent.) is "foreign"; 

 considering as foreign not only those born of foreign 

 parents (whether in America or elsewhere), but also half 

 of those who, though native-born, have one foreign parent. 

 This heterogeneity of population constitutes a grave social 

 and political danger ; particularly in the case of the 

 rapidly-growing coloured population. In more than one 

 sense, says the author, a black cloud may be said to hang 

 over the future of the Republic. 



Canada is not equally threatened by the dangers arising 

 from a mixed population. Yet, even in Canada, the fact 

 that the persons of French race form about a third part 

 of the population, and increase more rapidly than any other 

 known people, " cannot but be a source of anxiety and 

 possible trouble in the future." The solidity of our Aus- 

 tralian colonies is more perfectly satisfactory. 



Surveying the British Empire, the writer exhibits the 

 growth of the colonies relatively to the mother country 

 during the last half-century. Whereas the ratio between 

 the populations of the colonies and the United Kingdom 

 was 7:100 in 1841, it had become 21:100 in 1881. 

 Entertaining the idea of an Imperial Federation, our sta- 

 tistician thus estimates the balance of power in the 

 imagined Federal Parliament. If every 100,000 of 

 white population are entitled to one representative, then 

 61 per cent, of the Imperial Parliament would be 

 English ; the proportions for Scotland and Ireland would 

 be 9 and 12 per cent, respectively. 



But the political interest of these estimates must not 

 detain us from what is perhaps the most severely scientific 



