296 THE ENTOMOLOGIST. 



Entomoloijy with Special Reference to its Biolorjical and Economic 

 Aspects. By Justus Watson Folsom, Sc.D. (Harvard). Pp. i-xvi, 

 1-485. With five plates (one coloured) and 300 figures in the 

 text. London: Eebman, Limited. 1906. 



Classification having been so thoroughly dealt with by Comstock, 

 Sharp, and others, the author of the present volume on Entomology 

 has treated his subject chiefly from the biological and economic sides. 

 The thirteen chapters into which the contents of the book are divided 

 are arranged as follows : — i. Classification (pp. 1-26) ; ii. Anatomy 

 and Physiology (pp. 27-145) ; iii. Development (pp. 146-183) ; iv. 

 Adaptations of Aquatic Insects (pp. 184-192); v. Colour and Colora- 

 tion (pp. 193-215) ; vi. Adaptive Coloration (pp. 216-236) ; vii. 

 Origin of Adaptations and of Species (pp. 237-251) ; viii. Insects in 

 Kelation to Plants (pp. 252-275) ; ix. Insects in Relation to Other 

 Animals (pp. 276-306j ; x. Interrelations of Insects (pp. 307-344); 

 xi. Insect Behavior (pp. 345-365) ; xii. Distribution (pp. 366-392) ; 

 xiii. Insects in Relation to Man (pp. 393-408). There is also an 

 important list of entomological literature (pp. 409-466), grouped 

 under subject headings and chronologically arranged. The author 

 estimates that there now exist something like 100,000 titles, and he 

 has selected those that appeared to him to be most generally useful 

 and accessible. 



The book is abundantly illustrated, the figures in the text being 

 exceedingly good. One of the five plates is coloured, and represents 

 cases of protective mimicry among butterflies. 



The author claims to have incorporated a good many facts' that 

 have not hitherto appeared in text-books, and we think that in this he 

 is justified. Among other observations that attract our attention are 

 the following: — " Pictet, by feeding larvns of Vanessa nrticce on the 

 'lowers instead of the leaves of the nettle, obtained the variety known 

 as wticoides" (p. 196); and again, on p. 200: "Pictet has recently 

 found, however, that humidity, acting on the caterpillars of Vanessa 

 urticcc and V. poli/chloros, has a conspicuous effect on the coloration of 

 the butterflies. Thus, when the caterpillars were fed for ten days with 

 moist leaves, the resulting butterflies had abnormal black markings on 

 the wings, and the same results followed when the larvae were kept in 

 an atmosphere saturated with moisture." 



Unsuitable food certainly causes stunted growth. . Where larvfe 

 can manage, under such conditions, to struggle through and finally 

 attain the imago state, the imagines are usually dwarf and the markings 

 on the wings are sometimes more or less abnormal. In the case of 

 V. urticcB, larvae fed on hop produce very small butterflies, often 

 veritable pigmies. 



With regard to classification, we ought, perhaps, to note that the 

 system adopted is practically that of Brauer. Thysanura and 

 Collembola, however, rank as separate Orders. The earwigs (Derma- 

 ptera) are treated as a family of Orthoptera. Platyptera, of JPackard 

 and Carpenter, less the stoneflies (Plecoptera), takes the place of 

 Corrodentia, Brauer. The Embiidfe are here included in Platyptera, 

 and Packard's Mecaptera is retained for the scorpion flies, but the form 

 Mecoptera is used. Ehynchota gives place to Hemiptera. 



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