June 10, 1910] 



SCIENCE 



905 



were issued between 1901 and 1907, one, in 

 •which tsetse flies were treated by E. E. Aus- 

 ten, in 1903, and now this volume by the same 

 author covers the remainder of the Diptera. 



With the exception of Egypt the territory 

 covered in this work falls within the limits of 

 the zoogeographic province ordinarily called 

 the Ethiopian region. The record is con- 

 fessedly incomplete, even for the region indi- 

 cated, as the material available was at best 

 scanty, so that data concerning detailed dis- 

 tribution which are given in the last chapter 

 of the book are of relatively little value. This 

 defect, which is commented upon briefly only 

 in the preface, is of a serious character, since 

 many of the medical and military men who 

 will be called upon to use the book are likely 

 to draw unwarranted, though none the less 

 unfortunate, inferences from the brevity of 

 the records, but even more serious difficulties 

 arise from the omission of any reference to 

 those species not illustrated here. 



As natural in a work dealing with forms 

 that have so recently attracted particular at- 

 tention, museum material from different 

 countries is sure to be variable in amount and 

 the records compiled therefrom of very un- 

 equal value. Cape Colony naturally leads in 

 number of species recorded and Uganda is a 

 close second, but some states have only three 

 or four species listed, i. e., are represented by 

 very little material in the museum collections 

 and yet the text of this chapter conveys no 

 hints as to the proper method of interpreting 

 its lists. 



Of the Chironomidse the work describes and 

 figures one genus including three species; of 

 the Simuliidse, one genus with four species; 

 of the Psychodidae, one genus with a single 

 species; of the Tabanidae, seven genera with 

 eighty-four species; of the Muscidae twc 

 genera with five species, and of the Hip- 

 poboscidae one genus with three species. 

 These represent less than one half of the Afri- 

 can species already known. The illustrations 

 are very successful and in practical work will 

 be of immense value. Synoptic keys as well 

 as specific and generic descriptions are entirely 

 omitted and reliance placed rightly upon the 



accuracy of the figures which are admirably 

 done. The habitus and coloration of the 

 species figured are vividly represented, even 

 though few structural features are distin- 

 guishable in the plates. 



The author handles the bionomics of the 

 group treated in the broadest possible manner, 

 always from the point of view of disease dis- 

 semination, and the records of work done by 

 other investigators are particularly full and 

 well digested. In fact, the text is a mine of 

 information concerning the breeding, feeding 

 habits, appearance and relation to disease of 

 the individual families, genera and species. 

 The work is evidently well done and bears the 

 earmarks of accuracy. It also stands the test 

 as regards completeness of data concerning 

 the species treated. 



The book is certainly popular — in the best 

 sense of the word — rather than scientific, and 

 is sure to prove very valuable to investigators 

 experimenting on suspected species in the 

 field. It is also an important reference work 

 for those interested in this group either as 

 students of Diptera, of medical zoology, or of 

 disease transmission through insects. 



Henry B. Ward 



Aposporie et Sexualiie chez les Mousses^ II. 



Par El. et Em. Marchal. Bull, de I'Acad. 



roy. de Belgique (Classe de sciences), No. 



12, pp. 1249-1288. 1909. 



In previous papers on mosses the Marchals 

 have shown that the differentiation of sex in 

 certain dioecious species takes place in the 

 formation of spores in the sporangia, a single 

 sporangium containing both male and female 

 spores; further, that a regeneration obtained 

 from the cells of the sporophyte of a dioecious 

 species before the formation of spores will 

 develop into an hermaphroditic growth and 

 produce both archegonia and antheridia. 



The present paper deals with the sexual 

 character of the products of apospory or these 

 sporophytic regenerations. As might be ex- 

 pected, the aposporie outgrowth induced from 

 a mutilated young sporangium is found to 

 agree with the sporophyte in the number of 

 chromosomes in its cells, and with 2n chromo- 



