CHAP. XLI 



jiosa'ce^:. py s rus. 



887 



parallelopipedus Stephens, or lesser stag beetle, fig. 635. ; in which a is the 

 male, b the female, and c the larva), were, when grafted, so completely re- 

 stored to vigour as to stop the ravages of this destructive insect. As the 

 pear grafts readily on the different species of Morbus, whenever these trees 

 abound in woods, they may be changed into the finest sorts of French and 

 Flemish pears, by the simple process we have been recommending. 



Accidents, Diseases, Insects, $c. The pear, as a standard tree, is not liable 

 to have its branches broken off or disfigured by the wind ; nor is it nearly so 

 liable to canker as the apple tree. It is liable to the attacks of insects, but 

 certainly not so much so in fields as in gardens, and perhaps no where to the 

 same extent as the other edible fruit-bearing ifosaceae. On a large scale, there 

 is, perhaps, no cure worth attempting for insects or mildew on the leaves ; but 

 shallow planting, surface manuring, and regrafting, are excellent preventives 

 and correctives for these and all other evils to which the pear, and all other 

 i?osaceae, are liable. The larva of the Zeuzera ae'sculi hat., the Wood Leo- 

 pard Moth, (fig. 636. ; in which b is the larva, and a three of its spiracles or 

 breathing apertures,) lives upon the wood of the pear, as well as on that 



of the apple, service, quince, and probably of all the itosaceae ; as it is known 

 to do on the horsechestnut, lime, walnut, beech, birch, and oak. Some idea 

 may be formed of the manner in which this insect commits its ravages, by 

 inspecting fig. 637., which is a longitudinal section of part of the trunk of a 



637 



pear tree, to a scale of 3£ in. to a foot. The egg of the insect having been laid 

 on or in the bark, the young larva appears to have entered by forming a small 

 hole at a, and to have taken a downward direction in the soft wood; as the 

 cavity was not more than an eighth of an inch sunk into the wood till reaching 

 b, where it was rather more than three eighths, and was, when the section was 

 made, partly filled with the excrements of the larva. At c, the cavity begins 

 gradually to approach the centre of the tree, and take a regular shape, and 

 continues at about half an inch in diameter as far as d ; the distance from b to 

 d being 1 1 1 in. ; and the distance from d to the circumference of the tree 1 Jin., 

 as shown by the transverse section at/. The larva of this insect is of a deep 



