A. Iv ('.\MKK(»N 49 



Tiillgren reared the fiy from C he no pod i inn (ilhinii. As remedial measures 

 against the hirvae, he advoeates spraying the phints with a j)aranin 

 emulsion of the following comijosilion ; 10 litres of paraffin, | kilogram 

 of soft-soap to ]()() litres of water. Another method whieh he thinks 

 might prove eli'ective against the puparia in the soil is to spread the 

 latter with soot, guano or superphosphate. I'lohahly neither of these 

 methods would prove very effective in combatting the pest. 



In 1905 Professor Carpenter in Ireland reported the prevalence and 

 ravages of P. betae in that country. In his account of the life-history 

 he suggests the probability of there being foui- larval moults resulting in 

 five stadia. As far as my own observations are conceiiied with P. hi/o- 

 scyauu, I think I may pretty safely say that there are not more than four 

 stadia. The removal and burning of all affected leaves, as the author 

 states, is an effective but laborious method, where large crops are in- 

 volved, of temporarily minimising the ravages of the pest. Another 

 and more practical method which he advises, consists in the application 

 of a stimulating manure which, wdth a copious rain supply, would have 

 the effect, at least in the young stage, of forcing the growth of the plant 

 and strengthening it, the better to endure the attack of the maggots. 

 As the author further observes, the affect on the yield of a mangold 

 crop is most accentuated when the injury has been severe during the 

 period when the young foliage has recently burst forth. 



In America Chittenden (1903) deals briefly with the beet or spinach 

 leaf-miner, Pegomyia vicina Lintn., and asserts that infestation of 

 cultivated crops is often traceable to the negligent harbouring of weeds 

 such as lambs- quarters which, the author says, fulfil the function of 

 breeding-reserves on w^hich the fly can always rely in times of need. 

 As the fly is said to show a decided preference for spinach the author 

 proposes its use as a trap crop in sugar-beet fields. Otherwise the 

 methods of control are similar to those suggested by Professor Carpenter 

 whose source of information is Chittenden's memoir. 



4. Distribution. 



This species is widely disseminated throughout Europe and is pro- 

 bably to be found wherever beet, spinach and mangolds are cultivated. 

 Vassiliev (1913) records it from Russia and it is perhaps more prevalent 

 in Northern (where these crops are more generally grown), than in 

 Southern Europe Its ravages have been recorded from all over Great 



Ann. Biol, i ^ 



