Bibliographical Notices. 473 
dinide, and indicates the parts which are of most importance for 
taxonomical purposes ; and this is followed by a short account.of the 
habits of the perfect insects, and of their transformations, with a list of 
food-plants and a table for the determination of the larve, so far as 
the latter are known to him. One remarkable point specially re- 
ferred to is the occurrence of parthenogenesis among the Sawflies, 
which appears to be a much more general phenomenon than had 
been supposed. Of many species males only are known; of many 
others the males are in a miserable minority to the females ; and of 
several it has been directly ascertained that the eggs deposited by 
unfecundated females are in a greater or less degree prolific. Con- 
trary to the rule observed to prevail among the social Aculeate 
forms, these unfecundated eggs have occasionally produced male as 
well as female progeny. From this side, therefore, the Sawflies 
offer a most interesting and important field of investigation, and one 
which, from the ease with which the insects may be reared, may be 
cultivated without much trouble by almost any one. The investi- 
gation of the phenomena of parthenogenesis as displayed by the 
Gallflies, another family of which Mr. Cameron will treat, has 
already led to important results. 
Having cleared the ground, as above indicated, Mr. Cameron 
briefly discusses the chief systems of classification adopted by his 
predecessors, and then proceeds to develop his own views upon 
this knotty point. Of these we need say but little, except that the 
author seems to us to fall into the error, which is so rife in the 
present day, of making his classification too complicated. Nearly 
every systematic writer now appears to think that his main busi- 
ness consists in splitting up every group as much as the most minute 
analysis will enable him to do, the consequence of which is the 
establishment of a host of named subfamilies, tribes, groups, sec- 
tions, divisions, &c., which it is utterly impossible for any one not 
specially engaged in the study of the group so treated to carry in his 
head, and which must not only be quite useless for the higher pur- 
poses for which classificational units are wanted, but also stand in 
the way of the usefulness of the work containing them to those 
general students who may have occasion from time to time to con- 
sult special treatises for the mere determination of species. Thus 
the true Tenthredinide form seven tribes; and the first of these, 
Tenthredina, which alone is treated of completely in the present 
volume, includes three subtribes, Tenthredinides, Dolerides, and 
Selandriades; and although we cannot expect a corresponding 
amount of division in the succeeding tribes, the total number of 
terminal groups will still be considerable. At the same time Mr. 
Cameron will hardly be so great a sinner in this way as most of his 
contemporaries ; and he has provided students with a guide through 
the intricacies of the subject in the shape of an analytical table of the 
genera, in which all the intermediate divisions of the family are 
ignored. 
The strictly descriptive part of the present volume includes only 
the first tribe of the Sawflies, the Tenthredina, under which 202 
