NATURALIST. 



32G THE YOUNG 



and the first half of May these flies may be 

 seen busy sporting among the gooseberry 

 bushes, and flying from one tree to another. 

 If you watch a female attentively you will see 

 her scrutinise a leaf all over, running over 

 the surface and underneath several times, 

 until at last she seems to make up her mind 

 that it will suit her purpose, then she 

 descends to the under surface of the leaf, and 

 getting hold of the midrib by her legs, begins 

 at the bottom of the rib wherejt joins the 

 leaf-stalk, and deposits a row of eggs beauti- 

 fully arranged along the very summit of the 

 rib very nearly to the tip of the leaf. She 

 then goes to the side-ribs, and one after the 

 other decorates these with lines of oval 

 yellowish eggs. The underside of the leaf 

 now presents a beautiful appearance, each 

 rib being studded with eggs arranged in a 

 most systematic manner. In about ten or 

 twelve days the young grubs make 

 their exit from the eggs, and immediately 

 begin to gnaw minute holes along each side 

 of the ribs, and if the leaves are examined at 

 this stage a little grub will be found firmly 

 clasped to one side of each of these minute 

 apertures. If gardeners would pay attention to 

 them at this season, the number of grubs might 

 be greatly diminished, as for each leaf of this 

 description picked off and destroyed from 

 thirty to sixty grubs are got rid of at the 

 same time. But they never begin to see 

 danger until the trees are nearly stripped of 

 their leaves, when each grub has assigned 

 itself a separate establishment, and when the 

 work of getting rid of them has increased 

 itself from thirty to sixty fold. Children 

 could gather the leaves at this stage very 

 well, and it is one of the most effectual means 

 of getting rid of the pest. Kindling smoky 

 fires on the lee side of the garden when the 

 flies are flying about before they deposit their 

 eggs might also be done with advantage, as it 

 drives the flies away, though in this case it 

 only transfers the grubs from your own 

 garden to that of your neighbours. When 

 the grub changes its skin for the last time, 



it also changes color, and then greenish- 

 grey becomes a deep yellow. When 

 it has attained its full size, that is by 

 about the first or second week in June, it 

 leaves the tree and penetrates the earth to a 

 depth of three or four inches, where it spins 

 a transparent cocoon, and changes to a 

 chrysalid in the course of a week or ten days. 

 These chrysalids produce flies, which give 

 rise to a second brood of grubs, which eat, 

 grow, and descend to the earth like the first 

 brood, but these after they have constructed 

 their cocoons do not immediately change to 

 a chrysalis, but like many other saw-fly larva; 

 remain in the cocoon as a grub unchanged, 

 and only turn to a chrysalis on the approach 

 of spring, just before the time the flies are on 

 the wing. Should the grubs be neglected 

 when they are young, and are allowed to 

 become too numerous, flour of sulphur may 

 be dusted on the leaves in the early morning 

 when they are wet with dew. This is said to . 

 answer as well as powdered hellebore, which 

 is rather more dangerous in its application. 



This fly is one of a large tribe of Saw-flies, 

 and is therefore called the Gooseberry Saw- 

 fly, the scientific name of which is Nematus 

 Kibes ii. \ 



BRITISH BUTTERFLIES. 



By J. E. Robson ; with figures from life by 

 S. L. Mosley. 



I 



(Assisted by Contributors to the Y. N.) 



Genus VII, Leucophasia. 



" Leukos, white, Phasis, appearance." — 

 A.L. J 



A genus of only two species, both of which 

 occur in Europe ; one in Britain. 



ii SINAPIS. PI, 6, Fig. 2. 

 The Wood White. 

 " Sinapis, named from the Common 

 Mustard (Sinapis nigra), but the larva feeds 

 on Vicia cracca, Lotus, &c." — A.L. 



