204 The Scottish Naturalist. 



In each of the works above mentioned we meet with information of interest 

 and of value in regard to what is known of the distribution of the members of 

 the group discussed in it in Scotland, or, among the Spoiigtadoe, in the neigh- 

 bouring seas ; and the information of an indirect kind that may be learned 

 from them as to the lacuna in our knowledge of the Scottish fauna in these 

 groups, is no less valuable and interesting, though less satisfactory to our 

 pride. 



Looking into the monographs a little more closely, we may take them in the 

 order of publication. 



The volume on British Spongiadae is indispensable to all that are 

 workers in this group of animals, as well as to the proper interpretation and 

 comprehension of the synonymy of the species described in the three earlier 

 volumes, published by Dr. Bowevbank himself. In this volume are various 

 tables of much interest, including a classified list, geographical distribution, 

 166 pages of a review of the species described in the earlier volumes, with 

 synonyms of the species, and a catalogue of works and papers on sponges, by 

 the Editor, occupying 29 pages. A number of additional specie"; are also- 

 described here. 



The monograph on British Phytophagous Hymenoptera, by Mr. 

 Cameron, is, as might be expected from the author of it, a very exhaustive 

 and valuable work, though, as yet, only certain groups of the sawflies have 

 been discussed. From the author's thorough familiarity with those insects, in 

 respect to their occurrence in Scotland, as far as they have yet been worked in 

 this country, we are furnished with a very full representation of the state of 

 present knowledge in respect to their distribution with us. 



The usefulness of the book is largely increased by the introduction, which 

 commences with a good account of the structure and habits of the perfect 

 insects, especially with reference to the characters of chief value in the determi- 

 nation of the various groups in classification. Thereafter follows an account 

 of the modes of reproduction, with a full account of Parthenogenesis ', as 

 observed in the group of sawflies, and of the metamorphosis undergone by 

 the larvae. Under this head are given tables of the food-plants, with the 

 species that attack each, and a synopsis of the larvae, founded upon differences- 

 of structure, &c, so as to facilitate the discovery of the species of any previously 

 unobserved larvae. Some useful remarks follow, on the relative value 111 

 classification of the characters obtainable from the perfect insects, and from the 

 larval condition ; and very useful information is given in regard to the best 

 methods of collecting and preparing the insects, and more especially their saws, 

 for study. 



A most useful feature of the book is the presence of synoptical or analytical 

 tables of the genera, as also of the species in each gewus, a feature the import- 

 ance of which is felt by all working naturalists, but the difficulty and labour 

 involved in which can be fully realised only by those that have attempted 

 similar work. 



The systematic part of the monograph is wrought out with constant regard to 

 the avoidance of superfluous details, while giving all requisite information, 

 alike on the synonymy, on the distinctive characters, and on the distribution, 

 both in Britain and elsewhere, of each species. The plates are well-selected 

 and carefully executed, and the volume is one of the best that has been issued 

 for some years by the Society. We trust that the second volume may soon 

 follow to complete the monograph, especially as in it we may look for an 

 account of the gall-making Hymenoptera. In the meantime, we venture to 

 urge the desirability of rendering assistance to Mr. Cameron, if it is in the power 

 of any of our readers, by forwarding, lor his inspection, examples of Phyto- 

 phagous Hymenoptera from any part of Britain, but especially from those 

 provinces from which, as yet, no information is forthcoming. 



The Monograph of the British Aphides, by Mr. G. B. Buckton, com- 



