72 THE ENTOMOLOGIST. 



will form material for a second volume. The arrangement will 

 perhaps be set down as somewhat antiquated by those who accept at 

 once finy new scheme that may be pi-esented to them, but our author 

 holds the opinion that the attempts that have been made to increase 

 the number of orders are inadequate, and do not really deal equally 

 with the whole subject. Thysanura and Collembola are treated as 

 suborders of Aptera, but at the same time it is admitted that Collem- 

 bola has not so far been exhaustively worked out, and that " it is 

 possible that more grounds will be found for separating them as a 

 distinct order from the Thysanura — a course that was advocated by 

 Lubbock — than exists for dividing these latter from Orthoptera 

 proper." Aptera are regarded rather as primitive or little evolved 

 forms than as degenerate insects, and as to their being ancient or 

 ancestral, our author thinks that the reasons put forth for considering 

 them as such are insufficient. The general likeness of Campodea to 

 certain young insects of various kinds is **no more proof of actual 

 ancestry to them than their resemblances inter se are proofs of ancestry 

 to one another." 



In the chapter on Orthoptera we note, among other important 

 details, some interesting remarks on the recent discoveries about 

 Phyllium (leaf- insects) ; reference is also made to the term *' hypertely," 

 proposed by Brunner to express the idea that mimetic resemblance of 

 the design on wing-covers, as, for example, the imitation of leaf-spots 

 and veinings on the wing-covers of Pterochraza ocellata, is more 

 elaborate than mere purposes of utility require. 



Chapter XVI. is devoted to a lengthy consideration of the 

 Neuropterous family Termitidae, and comprises a great deal of in- 

 formation concerning these marvellous insects that will be new to 

 entomologists. 



The observations on May-flies are of an exceedingly instructive 

 character, and it is shown how external and internal structures and 

 habits in the various stages of these insects are all correlated. 



In the division Hymenoptera only points of general interest and 

 the parasitic groups are dealt with in the present volume ; the Aculeata 

 will be considered in the next volume. The phenomena, however, 

 connected with .parthenogenesis and production of sex are reviewed, 

 exception being taken to some of the conclusions founded on Dziergon's 

 observations. As regards polymorphism, or castes, in the social 

 Hymenoptera, our author is inclined to accept Herbert Spencer's view 

 that *' the sex is determined by degree of nutrition while the egg is 

 being formed," and that the subsequent production of a perfect or 

 imperfect female is dependent upon the nutrition of the larva. The 

 curiously varied conditions of the early life of parasitic Hymenoptera 

 is shown to be accompanied by equally remarkable embryological 

 peculiarities. 



We regret that space is not available for a more extended notice of 

 this excellent work, but we can earnestly commend it. It is capitally 

 illustrated, most of the figures being from original drawings ; and all 

 the information is thoroughly up to date. There is a growing desire 

 among those who are interested in insects to acquire a general know- 

 ledge of orderj they do not specially study; this work is the very 

 thing for their purpose. 



