100 



Normal on the pear. As the persimmon is unknown in this vicinity, 

 the species doubtless occurs on other trees. We have not found it, 

 however, upon cultivated fruits in numbers to indicate any proba- 

 bility of injury to them. 



This species is larger than that just described, shining black, 

 more or less pubescent, especially upon the head and thorax. The 

 frontal lobes are short, very obtuse and project forward from the 

 vertex. 



It is probable that Trioza pyrifoliee, like Psylla pyri, winters as 

 an adult and lays its eggs upon the young leaves in spring. The 

 young of the common sppcies fix themselves habitually upon the 

 young twigs or wood of the previous year, and, piercing the still 

 soft bark with their long beaks, remain stationary except when dis- 

 turbed. The fluid excrement of the louse attracts ants and other 

 syrup-loving insects, as does that of the Aphis. As the larvae obtain 

 their growth, they spread to the under sides of the leaves. Where 

 these insects are abundant, the continual drain upon the sap of the 

 young twigs arrests their growth, and the tips of the leaves and 

 twigs may die. 



The various insecticides found available for plant lice take effect 

 likewise upon these jumping leaf lice, the most promising topical 

 application doubtless being the kerosene emulsion with soap. 



8. The Willow Saw Flies. 

 (DoJeriis arvcnHis, Say; Doleriis hicolor, Beauv.) 



Order Hymenoptera. Family Tenthredinid.e. 



(Plate X. Fig. 7.) 



From one of the most intelligent and observant fruit growers of 

 my acquaintance, I have heard from time to time of a "steel-blue 

 tiy" which clustered in spring upon the buds and blossoms of the 

 pear, either eating them or blighting them and causing them to 

 drop. On the 30th March he sent me specimens from his pear 

 trees, and I found them to be the adults of the above two species 

 which are known as willow saw flies, — so-called because their green, 

 many-footed larvae feed on the leaves of willows. The evidence 

 against these saw flies lay in the fact that they were abundant and 

 busy upon the opening buds and fresh blossoms of the pear and of 

 some other trees, for many days in succession, and that the blos- 

 soms afterwards fell without setting fruit. Afterwards a similar 

 but more positive charge against these insects appeared in the 

 correspondence of the "Western Pairal" of Chicago, for May 17, 

 1881, as follows: 



"Enclosed you will find a couple of bugs that are working on 

 fruit trees here. They ruin many blossom buds by sucking the sap 

 out of them, sometimes causing them to fall off just before opening. 

 They make their appearance as soon as the trees begin to gro^y. 



