1899.] ' 163 



colour, he wisely adopts a soraewhat guarded attitude and points to the necessity of 

 further experiment and observation " if we are to obtain any real, as apart from 

 theoretical knowledge of the factors underlying variation." We may suggest that in 

 this connection the metallic and iridescent colours due to mechanical effects 

 dependent upon the superficial structure of the scales should not be disregarded. 

 Again in relation to defensive structure he remarks " there can be, we think, little 

 doubt that all the purely defensive structures of insects — hairs, flagella, glands, etc., 

 have been developed in response to the increasing attacks of enemies. That we 

 know very little about the subject is very evident, and workers have here an 

 unlimited field for observation." We trust the observers vf\\\ not neglect to toorJc. 



Before entering on his ninth chapter, which is devoted to classification, we had 

 hoped to find a description of the imago, pei'haps also of the pupa, worked out with 

 no less care than had been devoted to the larva and ovum, but this branch of the 

 subject (equivalent to the part of Hamlet in the play) has been practically omitted. 

 We trust that this is only deferred to a future volume, for Mr. Tutt's methods and 

 treatment are so exhaustive that we should expect to derive much useful information 

 from a carefully studied chapter. Although much has been written by the same 

 authors upon whom Mr. Tutt has drawn very freely (but always with due acknow- 

 ledgment) for those landmarks which have guided him in the general treatment of 

 his subject, there are many points in the structure of the Lepidopterous imago by no 

 means yet well understood, and of which an accurate appreciation could not fail to 

 be useful to systematists as well as to biologists, e.g., the homologies of the genital 

 segments with those of the generalised arthropod type have yet to be determined 

 and a correct terminology based on a careful comparison of these structures has yet 

 to be supplied. 



Before commencing the more useful part of his work, the author devotes one 

 chapter to the classification ot the Lepidoptera and allowing that his views ax'e governed 

 by the observations of Chapman, Comstock, Dyar, Packard and others, he evolves a 

 system of his own illustrated by a phylogeuetic tree which provides much food for 

 contemplation. In this chapter he reverts to the importance of the ovum as indica- 

 ting "a dichotomous division in Dyar's iVoc^Mina, one branch showing relationship 

 with his Micro- Lepidoptera through the Cossid8,the other through the Pyralids." On 

 this distinction he founds, T, his Noctuo-Hepialid stirps ; II, his Oeometro-Eriocraniid 

 etirps, also founding, mainly upon an examination of the eggs and in sympathy with 

 Dyar's views his third section the Sphingo-Micropterygoid stirps. Now, without 

 entering with too much elaboration into a discussion of the position of the different 

 families placed upon each of these lines of deviation we will take individual instances 

 and draw attention to the net results. The first series begins with the Hepialides 

 includes the Tortricides (why not TortricidcB !) and culminates in the Papilionides. 

 His second series beginning with Eriocrania includbs the Tineides (why not 

 Tineina ?) and culminates in the Oeometrides. His third series starting from the 

 Micropterygides includes Nepticula and the Psychides (macro-, and micro-), and 

 passing through the Pterophorides eventually arrives at the Satiimiides and 

 Spkingides. 



"We may at once state that each of" the root-families of these stirpes " might 

 equally well be put at the bottom of any stirps " — this is a quotation (vide p. 110) 

 and presuming that these root-families have originally branched out from the 



