Ninth Report of the State Entomologist 321 



turist for Januar}^, 1849, page 29. In this Dr. Plumb states that he 

 had lost several hundred young pear-trees between the years 1834 and 

 1838. It was not from the pear blight, which first shows itself in the 

 leaves. But in this attack the bark turns black, sometimes commenc- 

 ing in July, more often in August, and then again not until September. 

 It had not troubled him since 1838 until the present (1848), when he 

 believed that he had found the cause of the trouble in an insect which 

 he observed on the affected trees in September, although they might 

 have been there earlier. None were seen on the trees, not affected. 

 They looked to him like aphides, and jumped like fleas. Specimens 

 were taken from his trees about the middle of November, and sent to 

 Dr. Harris. 



From Dr. Harris' reply, published with the above, we learn that the 

 specimens received were in the winged state, both males and females. 

 From their injured condition and changed colors in drying, he was 

 xinable to name the species, but thought it probable that they were the 

 Psylla pyri of Europe. Their habits and transformation not unlikely 

 would be found to be similar to those given by European writers; 

 these are quoted by Dr. Harris, including the remedies recommended 

 by Kollar, substantially as given in the " Insects of New England " and 

 later editions of the same. The letter of reply concludes with the 

 following description of the specimens received from Dr. Plumb: 



Description by Dr. Harris of the Psylla. 



The insects were of a brownish color, with transparent wings, marked 

 by a few dark veins. Each measured one-tenth of an inch or rather 

 more, from the forehead to the tips of the closed wings. The front of 

 the head is notched in the middle. The eyes are large and prominent, 

 and with the thorax resemble somewhat in form those of our common 

 cicada. The antennae are longer than the body, slender, or threadlike, 

 and are tipp' d at the end with two little bristles. The body of the 

 female is pointed at the endy and is more of a reddish hue than that of 

 the male. 



In 1857, Dr. Harris saw the living insects on the trees at Salisbury. 

 Of these he has Avritten: *" On the 23d of July, I saw these insects on 

 the trees, some already provided with wings, and others advancing 

 toward maturity. The young ones [pupie] were of a dull orange-yellow 

 color. They were short, and were obtuse behind, and had little wing- 

 scales on the sides of their bodies [omitting what is given above of 

 the winged forms]; the head and thorax were brownish-orange, and 

 the hind body greenish. Their four ample wings were * * * * 

 colorless ***** 'pj^g European, P. x^yrl^ is said to vary in 



* Insects of New England, 1852, p. 203. Insects Injurious to Vegetation, 1868, p. 232. 



1893. 41 



