1914.] 67 



ttuarg. 



Ernest Olivier, a grandson of the celebrated entomologist, Antoine Guillaume 

 Olivier, died at Moulins, France, on January 26th, aged 70 years. He was 

 pi - esent at the Congresses at Brussels and Oxford, and read a paper at the 

 latter entitled " Necessite de FEmploi du Latin pour les Descriptions." For 

 many years he had paid especial attention to the Lampyriclse, and was thus 

 well known to Coleopterists all over the world. He was elected a Member of 

 the Societe Entomologique de France and of the Entomological Society of 

 London in the same year, 1873. For many years he had edited the "Kevue 

 Scientifique du Bourbonnais." 



%tV'UWB. 



"The North American Dragon-flies of the Genus Mshna." By 

 E. M. Walker, B.A., M.B., Lecturer in Zoology in the University of Toronto. 

 University of Toronto Studies, Biological series, No. 11, 1912 : pp. viii, 213, 

 with 28 plates. 



Whether one happens to open this fine memoir at the table of contents at 

 the beginning or at the beautiful series of plates at the end, one is at once 

 struck by the evidence of a strong and unusually exhaustive handling of the 

 subject. It is interesting to note the origin of the work. The view that some 

 of the nominal species of North American Mshna (as the author prefers to call 

 it) represented a complex, seems to have been reached independently by 

 Williamson and Walker from observations in the field. Not very long ago the 

 names of M. clepsydra, verticalis, and constricta made up the tale of the genus 

 in a good many State lists, but all that has been changed,and the preliminary 

 key published by Dr. Walker in the Canadian Entomologist, XL, pp. 377 — 91, 

 450-1, 1908 (itself a first rate working document) foreshadowed an enormous 

 increase in the knowledge of the genus, no fewer than eight new species being 

 there described. In the monograph under review, three of these species are 

 reduced to the rank of sub-species, the total number of species and sub-species 

 being twenty, excluding those separated by Williamson under the generic name 

 of Coryphseschna. 



As has been indicated, the subject is dealt with from very many points of 

 view. No matter which fauna or which aspect (excepting internal matters) 

 the student of Mschninse may be dealing with, a reference to Dr. Walker's 

 work will be indispensable. It is, therefore, unnecessary to go into details. 

 One may notice, however, the reduction of the nomenclature of the colour 

 pattern to definite shape, and also the very important figures of the accessory 

 genitalia of the $ not before used for purposes of classification in the genus. 

 Variation is dealt with under different aspects — climatic, geographical, and 

 colour — the existence of two types of colour in the females being discussed, one 

 in which the pale markings are mostly blue as in the males (homceochromatic), 

 and the other in which these makings are yellow or yellowish-green (hetero- 

 chromatic). These two conditions may be observed in British M. juncea. The 



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