54 REPORT ON INJURIOUS INSECTS FOR 1904. 



greenish owing to the green food contents of the intestine, which 

 are visible through the thin skin. 



Early in July the larvae leave the leaves and burrowing into 

 the ground to a depth of about three inches, they change to the 

 brown pupae, the flies appearing in from ten to fourteen days. 



Two or even three broods appear in the year. The pupae of 

 the last brood remain in the soil until the following spring, 

 occasionally, however, they develop and hybernate. 



PREVENTIVE AND REMEDIAL MEASURES. 



Spraying with i gallon of paraffin and ^-lb. of soft-soap, 

 well mixed in 10 gallons of water, towards the end of May, has in 

 some cases proved effective in preventing the flies laying their 

 eggs on the plants. 



Top-dressing with nitrate of soda and common salt has also 

 proved valuable in forcing on the plants. The quantities per 

 acre are from i to i cwt. of nitrate of soda and 2 to 3 cwt. of 

 salt. 



Any fertilising substance which favours rapid and healthy 

 growth is valuable. 



THE CARROT RUST FLY. 



Psila rosa (Fabr.). 



As a result of the determined efforts of many growers whose 

 crops were attacked by this fly in 1902 and 1903, it has been 

 considerably reduced, although it is still far too plentiful. 



Most correspondents emphasise the importance of thinning 

 early, before the plants are more than two inches high, and the 

 beneficial results obtained by watering, after thinning, with 

 paraffin and water, one gill of the former to one gallon of the 

 latter. A dressing of gas lime, where tried, has resulted in excel- 

 lent crops. 



THE GOOSEBERRY SAWFLY. 



Nematus ribesii, Scop. 



In the Pershore district of Worcester, in North Warwickshire 

 and in the South of Staffordshire, this fly still continues to 

 commit serious damage. 



* 



LIFE-HISTORY. 



Generally speaking, the flies make their first appearance 

 about the middle of April (April 2oth, 1903 ; 24th, 1904), followed 

 by two later broods during the summer. The female deposits 

 her eggs, which are white in colour and glistening, in long chains, 

 each one being deposited separately and placed in a slight cut 

 in the leaf. They vary in number, usually 15 to 40 on a leaf, but 

 60 to 70 are not uncommon, and are hatched out in about ten 

 days, this period, however, depends very largely on the climatic 



