MANGOLD-LEAF OR BEET FLY. 61 



time is lost in applying some remedy which would in all probability 

 have pushed on the crop through the time of infestation. 



The method of attack is for the fly to lay her white eggs (see figure) 

 (which look very like common " fly-blows ") on the under side of the 

 leaves. The maggots from these bore into the leaves, and there feed 

 for about a month. These maggots are little, legless, cylindrical grubs, 

 somewhat tapering to the head end, and whitish in colour, or some- 

 times greenish from the coloured juice on which they live showing 

 through the transparent skin. When full fed they turn to chestnut- 

 brown puparia, of the size and shape figured at p. 60 (nat. size and 

 magnified). This may be either in the leafage on which they have 

 been feeding, or in the ground beneath them, and from these chrysalis 

 cases the two-winged flies come out in summer in about a fortnight 

 or less. 



These flies may be generally described as of an ashy grey colour, 

 with some darker markings and with black bristly hairs, and are said 

 to appear as early as from March to May. These lay the eggs of the 

 first attack, and broods may continue through summer and autumn, 

 but two broods may be (under common circumstances) quite expected. 

 The last brood of the year may pass the winter either in chrysalis 

 state or sometimes as the perfect insect. 



The following observations are given much in order of the date in 

 which they were received. Amongst points of interest, one is the great 

 number of eggs which may be found on one leaf, and also how soon 

 the maggots hatch. Also the very valuable observations given in 

 detail by Mr. Haydon as to any treatment, or condition of soil, or of 

 situation, which is calculated to push on good growth, being beneficial 

 in lessening effect of the infestation, or carrying the plant over attack 

 (see p. 63j. The observation also of Mr. Coutts (p. 64), " They came 

 first just after being singled," is well worth notice, as drawing atten- 

 tion to the time when presence of attack and the need of remedial 

 measures may especially need attention. 



Amongst badly attacked specimens sent me, on June 22nd, by Mr. 

 John Hilder (bailiff to Mr. P. Beresford Hope, of Bedgebury Park, 

 Fhmwell, near Hawkhurst), I found about one hundred and forty-six 

 eggs of the Mangold Fly, possibly more, on the under side of one Man- 

 gold leaf, only a little more than three inches and a quarter in the 

 length of the blade. Some of the leaves were already severely 

 blistered. Mr. Hilder noted how very quickly the maggots hatched 

 from the deposited eggs. 



On the 24th of June, Mr. C. E. Bruce Foy, writing from MoUington, 

 near Banbury, with badly attacked specimens accompanying, mentioned 

 that his Mangold plants were infested this year with the grub in the 

 leaves, of which he sent samples, and that several farmers in the 



