233 



Emelianov (I. v.). MtcTHbifl onbiTHbifl ciaHuin no npMKJiaAHOti 

 SHTOMOJioriM btj CoeflMHeHHbixij LUiaTaxt m KanaAt. [The local 

 stations of Applied Entomology in United States and Canada.] 

 pp. 61-68. [See this Review, Ser. A, iii, p. 9.] 



During the discussion of the papers by Pospielov [see this 

 Review, Ser. A, iii, p. 239] and Emelianov, it was pointed out that 

 in the countries visited by the authors, the population is more 

 prepared for the task of making use of the information issuing from 

 Entomological Institutions and takes up a different attitude towards 

 the work of the latter. The author attributed this to the different 

 economic, educational and agricultural conditions prevailing in those 

 countries. 



Znamensky (A. v.). Ktj Bonpocy o eniflHin Terflnepaiypbi Ha paaemie 



nyrOBOrO MOTblJIbKa. [On the question of the effect of tempera- 

 ture on the development of Phlyctaenodes stictiailis, L.] pp. 

 69-77. 



Experiments are described on the development of pupae of Phlyctae- 

 nodes {Loxostege) sticticalis, L., the object of which was to observe 

 the effect of various temperatures on the fertility or sterility of the 

 females. It has been frequently noted of late years, that the 

 females of P. sticticalis are often sterile, and according to Professor 

 V. P. Pospielov this arises through their emerging from the pupae in a 

 state of sexual immaturity, which he regards as a more or less normal 

 condition, at least in the case of the females of the second generation, 

 and attributes it to the influence of high temperature and dryness. 

 This interferes with the normal development of the ovaries during 

 the pupal stage, while the continued effect of the same causes after the 

 insects have hatched, renders the females permanently sterile. 



Attempts were therefore made to ascertain to what degree the pre- 

 imaginal development of the ovaries depends on the temperature 

 to which the pupae are subjected, and how far this affects the further 

 development of the eggs. Six lots of mature caterpillars were put into 

 six chambers of a polythermostat, the temperature in the different 

 chambers varjdng from 8° to 35° C, being kept constant during the 

 whole period of the experiment. Although all the caterpillars were in 

 the same state of readiness to pupate, in a temperature of 35° C, they 

 pupated in two or three hours ; in 26° C, in five days ; 19° C, seven 

 days ; 16° C, 14 days ; 12° C, 18 days ; and 8° C, 28 days. The 

 emergence of the imago varied from 17 days in the first chamber to 

 29 in the fourth ; no emergence took place in the remaining two 

 chambers (with the temperatures of 12° and 8° C), the caterpillars 

 having built cocoons, but not pupating. The optimum temperature 

 seems to lie somewhere between 26° and 35° C. Part of the emerged 

 insects of each lot were immediately dissected, the remainder being 

 kept in the insectarium ; one lot of these was fed on sugar-syrup, 

 the other receiving no food whatever. The dissection of the 

 females hatched in the first chamber (35° C) showed that the whole 

 of the abdomen, and even the first segments of the thorax, was filled 

 with the fat-body in which the eggs were quite buried. The females 

 of the second lot (26°) also showed a greatly developed lat-body and 



(C150) B 



