472 



FRUIT GARDEN. 



the plane of the leaf. It forms a slight open- 

 ing in the cuticle of the leaf, merely cutting 

 through the surface, but not piercing through 

 the whole leaf, applying its mouth to the edges 

 of the opening thus made, and feeding upon 

 the parenchyma alone. It then by degrees in- 

 troduces the fore-part of its body between the 

 two surfaces of the leaf, and mines the leaf 

 round the spot where it made its first perforation, 

 to the extent of half an inch or more in diameter, 

 leaving the surface of the leaf marked with a 

 broadish blotch. It moves from leaf to leaf, 

 and proceeds in each case exactly as above. 

 When it has attained its full size it ceases feed- 

 ing, and begins to attach itself to the branches 

 or trunk of the tree, and there undergoes its 

 transformations, appearing again in its moth 

 state in the July following. The body and fore 

 wings of the perfect moth are of a dirty white 

 colour, speckled over with very minute dark- 

 coloured dots. The hind wings are of a brownish 

 colour, the legs being hairy. In size it is some- 

 what more than half an inch from tip to tip of 

 the wings. The best way of ridding the trees of 

 this pest, is by watching for the insect when it 

 first commences its attack on the foliage ; it 

 can then readily be seen standing on end, as it 

 were, on the under surface, and from its position 

 and size can be easily picked off. 



The pear-tree oyster-scale (Aspidiotis ostrece- 

 formis), fig. 203, is much less frequently met with 

 Fig. 203. 



PEAR-TREE OYSTER-SCALE AND TERFECT INSECT. 



than the apple mussel-scale, fig. 191; or, from 

 its external appearance being so similar to the 

 colour of the bark of the pear tree, may be 

 either overlooked by cultivators, or mistaken 

 for the bark. Its effects are similar to those of 

 the apple mussel-scale, and the means of de- 

 struction are no doubt the same. The reader is 

 referred to our notice of that insect. 



The Paradoxical pear platygaster (Psilus 

 Boscii Turine, Platygaster Boscii Latreille, and 

 Inostemma Boscii of Haliday), is a vex-y minute 



hymenopterous insect, scarcely a line long, 

 yet very destructive to the fruit of the pear. 

 Like the large and small pear-midges, the black- 

 gall midges, &c, they lay their eggs in the blos- 

 som, and the larvae exist within the fruit. Such 

 pears as are attacked are, according to Kollar, 

 easily known, " because their growth far exceeds 

 that of the other pears, and they (the insects) 

 have attained a considerable size when the petals 

 have scarcely fallen off. When this is seen, it is 

 certain that one sort of larva or other is to be 

 found in the core. When a pear thus infected 

 is permitted to grow, it increases in size for some 

 time, loses its roundness and bright green colour, 

 and becomes longer, as if pressed inwards all 

 round the middle part. This is the period when 

 the larva begins to attain its full size, and there- 

 fore the best time for taking them from the 

 tree ; for if rainy weather ensue,, cracks are 

 found in the pears, by which the larvae find a con- 

 venient outlet to precipitate themselves to the 

 ground. It is seldom that the larva? are found 

 in the core of those pears lying on the ground, 

 if the rainy weather is of long continuance ; and 

 when this is the case, most of the pears remain 

 on the tree till they are almost completely 

 rotten. If the weather be dry, they usually fall 

 off sooner; and in that case those pears that are 

 lying on the ground should be picked up and 

 destroyed, because, when in that state, the larvae 

 often remain long in them." This is no doubt the 

 most judicious way of thinning these destructive 

 creatures, and those allied to them. They have, 

 besides, their natural enemies, which feed upon 

 and destroy them, particularly a gold-shining 

 hymenopterous insect which makes its appear- 

 ance exactly at the same period as the platy- 

 gaster and pear midges. 



The Black-gall midge (Cecidomyia nigra, 

 Meigen) is very destructive to the blossom of 

 the pear, and to a great extent produces those 

 failures in the crop which are usually set down 

 as caused by easterly winds, late frosts, &c. 

 They lay their eggs in the blossom as soon as 

 the petals begin to show themselves out of the 

 calyx, by piercing through the petals with their 

 long ovipositor, and depositing their eggs on the 

 anthers, to the number generally of ten or 

 twelve, often more, for as many as twenty larvae 

 have been found in one pear. The eggs, if the 

 weather is warm, will be hatched in four or five 

 days ; and before the blossom has fully expanded, 

 they descend to the core of the fruit, where 

 they separate, and begin to devour the fruit in 

 all directions. By the time they have eaten up 

 all the pulp they have attained their full size, 

 and only wait an opportunity of escaping from 

 their feeding-place and find their way to the 

 ground, which they do by availing themselves 

 of cracks in the fruit, or when it becomes partly 

 decayed, so that they can reach the surface, 

 from whence they spring to the ground and 

 bury themselves. Sometimes they eat their 

 way out of the fruit to effect their escape, and 

 at other times remain for a considerable time 

 within the pear, even when it has fallen from 

 the tree. The larvae of so many insects are 

 found within the prematurely fallen apples and 

 pears, that it is well to gather all such up, and 



