254 EXPERIMENT STATION RECORD. 



Some factors influencing' insect development, (.'. IIknningh {Biol. CcnIhL, 

 21 (1907), pj). 32'i-337, pi. 1). — The experiments reported in this paper were 

 carried out chiefly on Tom lens typagrdpliiin. It was found that the deposition 

 of the eggs could l)e delayed at least 2 days by lowering the temperature 

 3 or 4° C, or by increasing the moisture content of the area. The same modi- 

 fication of these factors also prolonged the period of egg laying sometimes to the 

 extent of 5 days. Similarly the larval and pupal stages were considerably 

 elongated by increasing the moisture content or reducing the temperature. 



Increase in the weight of pupae kept in an atmosphere with a high con- 

 tent of carbon dioxid. Countess von Lindkn (Sitzber. Katiirliist. Vcr. Prcii.ss;. 

 Rhclidandc it. Westfalois, 1007, I, pt. A, pp. l-ll). — Pupfe of a number of 

 species of lepidoptera were kept in an atmosphere containing 5 per cent or mox-e 

 of carbon dioxid. By means of careful weighings and gas analyses, it was 

 determined that the pupse absorb carbon dioxid from the atmosphere and 

 utilize it directly in the formation of carbohydrates, thus increasing their 

 weight. 



Some critical observations on the European species of the genus Chermes, 

 E. R. BuRDON {.Jour. Econ. Biol., 2 (1908), No. 7/. pp. 119-1J,8, pis. 2).— The 

 author gives a detailed account of the various developmental forms observed in 

 10 species of this genus. In discussing material for the identification of species 

 he takes up the characters furnished by the insects themselves and also the 

 characters furnished by the galls produced by the insects. 



Intercortical scale formation and the development of Diaspis fallax, H. 

 MoRSTATT (Centbl. Bakt. [etc.], 2. AU., 20 {1907), No. J,-5, pp. 150-153).— 

 According to the author's observations the scale of the female of Diaspis faUa.r 

 and certain other scale insects of this group is partly composed of the extreme 

 outer layer of cork tissue of the host plants upon which the scales are found. 



The biology of plant lice, A. Mordwilko (Biol. CeiithL, 27 (1907), pp. 

 529-550; 561-575; 77/7-767; 769-816, figs. 25).— The author discusses the whole 

 cycle of the biology of plant lice with particular reference to heterogony, 

 especially as observed in plant lice and in the alternation of generations which 

 characterizes a large number of species of this group. 



The interrelations of ants and plant lice, A. Mordwilko (Biol. Centbl., 27 

 (1907), pp. 212-22.',; 233-252, figs. .5).— An elaborate description is given of the 

 mutual relations between various species of ants and the plant lice which they 

 attend. Particular attention is given by the author to a discussion of the 

 theories for explaining the origin of this relation and its economic significance. 



The polymorphism of ants, V7ith an account of some singular abnor- 

 malities due to parasitism, W. M. Wheelkr (Bui. Ainer. Mits. Nat. Hist., 23 

 (1907), pp. 1-93, pis. 6).— Detailed observations were made on Orascma viridis 

 and a si)ecies of ]Mermis as parasites in ant colonies and on the effects pro- 

 duced upon the ants by these parasites. A large portion of the paper is occupied 

 with a general discussion of the origin of parasitism of ants as related to the 

 polymorphism observed in this group of insects. 



The fungus-growing ants of North America, W. M. Wheeler (Bui. Amcr. 

 Mils. Nat. Hist., 23 (1907), pp. 669-807, pis. .5).— Detailed descriptions are 

 given of a number of species of Atta and other genera of this family of ants 

 which are distinguished by their habit of cultivating fungi for food. The 

 theories which have been proposed for explaining the origin of this habit are 

 critically discussed by the author. 



Wild bees, wasps, and ants, E. Saunders (London, [1907], pp. Xlll+l.'/h 

 pis. .',, figs. 28). — The pnrjmse of this volume is to present in a simple form an 

 account of the wild species of bees, wasps, ants, and other related hymenoptera 



