SERVICE OF BIRDS IN THE ORCHARD. 153 



cies of the caterpillars, trusting them to the care and pro- 

 tection of the birds. I visited the place occasionally during 

 the summer, and in the fall saw that measures were taken, 

 as usual, to attract the birds. On November 12 I returned 

 for the "winter, and noticed no evidence of insect injury 

 among the fruit trees. A small flock of Myrtle Warblers 

 and some Goldfinches were very busy among the apple 

 trees, and were paying particular attention to the pear trees 

 near the house. I was told that they had been coming there 

 for about two weeks. Realizing at once that they must be 

 engaged upon those leafless trees in the suppression of some 

 insect, I examined the trees casually, but at first was unablp 

 to find the object of their quest. One of the birds was 

 watched closely. It was taking something from the lower 

 sides of the twigs and the crevices between them. With a 

 glass it was seen to take some very small insects that were 

 hiding in these situations. Evidently the insects were no 

 longer plentiful, as the birds had to search somewhat to find 

 them, and the only way in which I could find a specimen 

 was by driving a bird away just as it was about to attack the 

 insect, and then examining the twig. Three tiny insects, 

 which appeared like little cicada-shaped flies, were found 

 and secured in this way. Two of these were forwarded to 

 Dr. L. O. Howard, chief of the Bureau of Entomology, at 

 Washington, who identified them as adults or imagoes of 

 the pear tree psylla (Psylla pyri), a pest imported into this 

 country from Europe about 1832. According to Circular 

 No. 7, second series, issued from Dr. Howard's office, an 

 overwhelming invasion of this insect occurred in the year 

 1894 in one of the largest pear orchards in Maryland ; there 

 were similar occurrences in Virginia and New Jersey. This 

 insect has long been known as a pest of the pear tree. It is 

 a true bug, of the order Homoptera, intermediate between 

 the scale insects and the plant lice on the one hand, and the 

 cicadas and" larger plant bugs on the other. The Psyllidae 

 are commonly known as the jumping plant lice, on account 

 of their vaulting ability. They are extremely prolific, having 

 several broods each year. In the infested Maryland orchards 

 the leaves and fruit fell, the latter before it was half grown, 



