PEAB. LIMBS — PEAR BAKK-LOUSE. 107 



their whole length, and are about one-fourth the length of the 

 body. They are composed of several small joints and are clothed 

 with a few fine longish hairs. 



I have not had an opportunity to trace the history of this insect 

 further, but doubtless, like the other species of this genus, the 

 young larvae in a short time fix themselves to the bark and in- 

 crease somewhat in size, but retain the same form through the 

 winter; and early in the spring the males enter their pupa state, 

 and soon after come out under the form of minute delicate flies 

 with only two wings; whilst the females, without undergoing any 

 very obvious change, gradually grow to the size and form of the 

 hemispherical scales already described. 



A parasitic insect, which probaly pertains to Mr. Westwood's 

 genus Coccophagus, in the Family Chalcidid^ and Order Hyme- 

 NOPTEEA, lives in the bodies of the females, subsisting upon their 

 young. The worm, which is doubtless similar to that noticed 

 under scales of the Apple bark-louse, but of a larger size, having 

 completed its changes makes its escape through a rather large 

 round hole which it gnaws in the scale. Several scales were ob- 

 served which were thus perforated, the hole being rough and 

 jagged at its edges, and the scale being of a paler color at the part 

 surrounding this perforation. 



This insect cannot but prove very detrimental to the pear tree 

 when the females are present in such numbers as they were in the 

 instances in which I met with them. No tree can remain thrifty 

 and vigorous with such a number of tiny beaks inserted every 

 where in the smooth tender bark as a few of these females upon 

 each limb will breed . Fortunately they are of s uch a size that they 

 can easily be seen upon a careful inspection of the under sides of 

 the limbs, and can readily be removed. They should be looked 

 for the latter part of June, as the females will then have attained 

 their full size; arid wherever they are discovered the under side 

 of the limbs should be rubbed with a brush or a sponge to dis- 

 lodge every scale which can be perceived. Being at this time 

 nearly or quite dead, and wholly destitute of legs, they will be 

 unable to reascend the tree when brushed oif, nor are the young 

 sufficiently strong to crawl away from their parents. 



