The Scottish Naturalist. 205 



were previously unknown, or at least nothing was known of their life-history or 

 pleted in the fourth volume, quite recently issued by the Ray Society, is un- 

 doubtedly a very important addition to the literature of this family of insects 

 as well as the only really comprehensive work on those species that have been 

 met with in Britain. Nevertheless, even a passing inspection of the volumes 

 shows that there is still much to be done ere we can claim a thorough acquaint- 

 ance with the group. 



That few entomologists have occupied themselves with the Aphides explains 

 the fact that their distribution, except in the case of species noted for their 

 powers of doing injury to cultivated crops, is for most species very little 

 wrought out ; and, for the same reason, we cannot doubt that the number of 

 species will be largely increased, when more general attention is paid to them. 

 In the meantime, we may notice a great deficiency of information from Scot- 

 land. In this group, not less than in various others, there is great room for 

 Scottish workers. 



The existence of this work, by Mr. Buckton, renders it comparatively easy 

 to commence the study, with some hope of being able to ascertain what is 

 already known about British Aphides, as the figures are excellent aids to the 

 determination of the species, and the descriptions are in all cases full, and a 

 life-history is in many cases given. 



The usefulness for convenience of reference would, perhaps, have been 

 greater had the diagnostic characters been separated out from the mass of type 

 in some way. Under a good many of the species, it is somewhat difficult to 

 pick out at once the important points from among the details that accompany 

 them. Condensation might have reduced the size and price of the work, while 

 not detracting from its real value. 



In this volume we find articles on several subjects of interest in the economy 

 of Aphides, of which we may note those on their " Economical Relations to 

 Ants," on their reproduction, on fossil species, with descriptions and figures of 

 all as yet published, on the natural and best artificial checks to their increase, 

 and on the preservation and mounting of Aphides for the microscope and for 

 the museum. A " Bibliography " of the authors that have written on Aphides 

 concludes the volume. We cannot doubt that the publication of the mono- 

 graph will give a powerful stimulus to the study of these insects among us in 

 Scotland, no less than in other parts of Britain. 



"The British Oribatidee," by Albert D. Michael, F.L.S., &c, is the 

 volume issued to subscribers for the year 1S83, and appeared in May, 1884. 

 The group of mites treated of in it form a well-defined division of the Acarida, 

 but one that has found few students previously. Beyond scattered articles in 

 magazines, the only works that attempt a scientific study of these animals are 

 Koch's " Deutschlands Crustaceen," &c, his " Arachnidensystem," and 

 Nicolet's Monograph of the Oribatidee of the neighbourhood of Paris. In the 

 preface to his work, Mr. Michael says : — " The reader will kindly remember 

 that this book is the record of work done in the scanty leisure of a very busy 

 man ; it does not profess to be a monograph." That it is a most valuable 

 addition to previous records on the subject is plain to the eye of any zoologist 

 that examines the book with the slightest care. A very striking feature in it is 

 the number of species of which the author was able to trace the transformations, 

 despite the care that was required in the case of each, sometimes for periods of 

 over a year. In this way he was enabled, through identifying the various and 

 often very different forms passed through by the same creature, to show that 

 many of the species described by Koch and others were only immature condi- 

 tions of other and well-known species. 



As regards our knowledge of the British species of the group, the progress 

 made by him is yet greater, inasmuch as " some five years ago there was 

 hardly a record of the capture of any species in the British Isles, and very 

 little was known concerning them." In this work Mr. Michael describes forty 

 British species, of which most are figured in the fine plates, while in many of 

 them the immature stages are described and often figured. Many of these 



