1922.] 
Reviews and Abstkacts. 
319 
REVIEWS AND ABSTRACTS. 
Insect Transformation, by George H. Carpenter, I).Sc., Professor of 
Zoology, Royal College of Science, Dublin, Sec. Royal Irish Academy. 
Methuen and Co. (Limited), 36 Essex Street, London, W.C. 282 pages, 
4 plates, and 124 illustrations in text. 
Professor Carpenter’s researches on various groups of insects are so well 
known to entomologists in general that a new book from his pen is sure 
of a cordial welcome from them. This work is, to use the words of his 
preface, 44 designed to serve as an introduction to the study of growth and 
change in the life of insects,” and he hopes that it 44 may be of some 
service to serious workers in entomology as w y ell as to. beginners.” 
The plan of the book is a good one. The reader is first introduced to a 
few familiar examples of the changes that accompany growth in the lives 
of insects, and the morphology of the adult insect is fully explained before 
any attempt is made to classify the different types of change met with. 
Then, by the use of the grasshopper, dragon-fly, and moth as examples, the 
reader is led to the generalized conceptions to which entomologists have 
come to apply the comparative terms 44 ametabolic,” 44 hemimetabolic,” 
and 44 holometabolic.” Following Dr. Sharp’s lead, the phenomena of 
metamorphosis amongst winged insects is then divided into its two main 
sections, the 44 open ” type of wing-growth (Exopterygota) and the 44 hidden ” 
type (Endopterygota), and examples are given illustrating the metamor¬ 
phosis of each of the orders of insects that come under these two headings. 
This leads, in chapter v, to the consideration of wingless insects, and the 
effect of parasitism on the form of an insect, and this secondary winglessness 
is then contrasted with the primitive unaltered winglessness of the true 
Apterygota, the spring-tails and the bristle-tails. The ground thus covered 
enables the author to give, in chapter vi, a concise classification of the 
Insecta, in which twenty-three orders are recognized. Chapter vii deals 
with the correlation between the growing insect and its surroundings, and 
we are here introduced to the secondarily aquatic larvae of certain Diptera 
(sandfly, mosquito, <fec.), the habits of burrowdng and sucking the juices 
of plants, the formation of galls, the parasitism of one insect by another, 
and finally the care of the helpless young by the adult, as in the case of 
ants. The last chapter deals with the general problems of insect trans¬ 
formation, and emphasizes the apparent paradox that whereas in other 
groups of animals low-grade forms are found to undergo more profound 
changes than high-grade forms, yet in the case of insects the reverse is true, 
metamorphosis becoming more and more complete as we pass upwards to 
the more highly evolved forms. The reason for this is very clearly ex¬ 
plained, and this part (chapter viii) is recommended as the best in the book, 
particularly the illuminating discussion as to the probable primitive type 
of insect-larva, the evolution of the two types of wing-growth, and the 
short but excellent summary of the palaeontological evidence. 
Any book dealing with so large a subject can scarcely claim to be original, 
but the author certainly has as much claim as any one to be considered 
an authority on his subject. Thus it is noted, as is to be expected, that 
he has introduced illustrations and examples from a number of recent 
researches by modern authors, which greatly enhance the value of the book. 
