346 



the total number laid by each female varying from 70 to 90. They 

 hatch in about six days, and the emerging larvae eat through the 

 cuticle into the parenchyma of the leaf. The larval stage averages 

 16| days, during which time three moults occur. As a rule the larvae 

 remain in the mine in the leaf until the first moult, after which they 

 feed externally, but occasionally the second stage larva may make 

 a fresh mine. If the leaves of the food-plant are very thin, the larvae 

 feed externally from the beginning. The cocoon is formed on the leaf, 

 and pupation lasts on the average IH days, giving a total life-cycle 

 from egg to adult of about 34 days. This time varies, however, accord- 

 ing to weather conditions and latitude. Farther south, in the vicinity 

 of Voronezh, the total cycle is from 18 to 19 days ; the egg-stage three, 

 larva ten, and pupa five to six days. 



The number of generations in the year in the Petrograd district has 

 not been definitely ascertained ; there are probably three, though 

 occasionally only two may occur, or sometimes a partial fourth. From 

 the middle of July to about the middle of September all stages of the 

 moth may be found simultaneously on cabbages. Hibernation occurs 

 in the pupal stage. 



Natural enemies include various birds, the predaceous larvae of 

 Coccinella septempimctata, T., and C. {Propylaea) quatuordecimpunctata, 

 L. A list of all the known Hymenopterous parasites is given. Of 

 these, the Ichneumonid, Angitia fenestralis, Holmgr., and a Braconid 

 have been reared from the larvae near Petrograd, and Sagaritis latrator 

 Grav., Tamelucha plutellae, Ashm., and Phaeogenes plutellae, Kurd]., 

 have been recorded from other parts of Russia. 



The remedial measures suggested by various authors are discussed, 

 but their efficacy when applied under existing conditions in North 

 Russia has not yet been proved. Spraying with stomach poisons is 

 not advocated owing to adverse climatic conditions ; but the need for 

 the application of measures such as clean cultivation, the planting of 

 trap-crops, and general care of the plants, thus increasing their 

 resistance, is emphasised. 



Cholodkovsky (N. a.). nonoBOM Annapaie XpeHOBoro JlMCToeAa 



[Phaedon cochleaviae, Fabr.). [On the Genital Apparatus ol 

 Phaedon cochleariae, F.] — MsBeCTHfl HOAOTfleJia Eopb5bl C 

 BpeflmenflMM npM neiporpaACKOM KoMMTeie no CenbCKomy 

 X03flMCTBy [Bull. Sub-Scdion Control Plavt Pests attached to 

 the Petrograd Committee of Rural Economv], Petrograd, i, April 

 1919, pp.' 100-102, 2 figs. [Received 13th May 1921.] 



The genitalia of both sexes of Phaedon cochlearie, F., are described. 



Cholodkovsky (X. A.). SaivieTKa Tono/ieBOii Tne (Schizoneura 

 passerinii, Signoret). [Note f)n the Poplar Aphid, Schizo- 

 neura passerinii, Sign.]— MsBeCTIIfl riOAOTfle/ia Bopb6bI C 

 BpeAMTenflMH npn nerporpaACKOM KoMMrere no Ce/ibCKOMy 



XoaHMCTBy [Bidl. Snh-Scction Control Plant Pests attached to 

 the Petrograd Committee of Rural Economy^, Petrograd, ii, 

 no. 2, 1919, pp. 3-6, 3 figs. " [Received 13th May 1921.] 



Schizoneura passerinii, Sign., is recorded on poplar {Populus 

 halsamea) in the vicinity of Petrograd. At the beginning of July 

 1919 only apterous forms were noticed, the nymphs appeared towards 



