ATTACKING THE BRANCHES. 145 



in volume and protrudes from under the scale. Early in the 

 season they crawl out and distribute themselves over the 

 smooth bark, appearing as minute whitish specks. When 

 magnified, they are found to be of an oval form, somewhat 

 flattened, about one-hundredth of an inch long, of a dull- 

 white color, with six legs and short autennffi. The young 

 larvse soon attach themselves to the bark, which they punc- 

 ture with flieir beaks, living on the sap, and during the season 

 materially increase in size. They pass the winter in a torj)id 

 state, and in the spring the males enter the pupal condition, 

 and subsequently appear as minute two-winged flies, while the 

 females gradually grow to the size and form of the scales 

 already referred to, after which, dying, their dried bodies 

 remain to serve as a shelter for their offspring. This is 

 believed to be the same insect as occurs upon the pear-tree 

 in Europe, and is said to be peculiar to the pear. 



Remedies. — Fortunately, these insects are of such a size that 

 they are easily seen. They should be looked for during the 

 latter part of June, at which time the females will have 

 attained their full size, and, when discovered, should be 

 promptly removed. The under side of the limbs should 

 also be well scrubbed with a brush dipped in some alkaline 

 solution. 



A small, four-winged parasite lives in the bodies of the 

 females, feeds upon their substance and destroys them, and 

 forms a chrysalis under the scale. When this fly matures, it 

 gnaws a round hole through the scale and escapes. 



No. 70.~The Pear-tree Psylla. 



PsijUa pyri Schmidb. 



During the middle of May, when growth is rapid, the smaller 

 limbs and twigs of pear-trees are sometimes observed to droop ; 

 a close examination reveals a copious exudation of sap from 

 about the axils of the leaves, so abundant that it drops upon 

 the foliage below, and sometimes runs down the branches to 

 the ground. Flies and ants gather around in crowds to sip 



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