INSECT FOOD. 29 



watched for three hours, August 23. Catbirds and vireos, though 

 numerous, did not molest the larvse, but a pair of yellow-billed cuckoos 

 continually extracted them from the webs. The destruction of this 

 insect is an habitual practice with the cuckoo. In a single stomach of 

 the species examined by Professor Beal there were 325 of the larvae. 



Saw-flies. — In August, 1896, also, the willow saw-fly {Pteromm) 

 was defoliating the willows farther up the gully. No birds were 

 observed preying on it, though the cuckoo is known to relish saw-fly 

 larvae, sixty of which were found in a cuckoo's stomach examined by 

 Professor Beal. The cornel bushes of the same gully were almost 

 every year stripped by the larvae of another saw-fly {Ilarpipharus 

 va/rmniis). On July 30, 1895, they covered every large bush, and 

 later they devoured all the foliage. A dozen catbirds and several 

 birds of other species were constantly near the bushes, but evidently 

 did not touch the insects. A repetition of these circumstances was 

 noted August 2, 1896. An interesting outbreak of the pine saw-fly 

 {Lophyrus) occurred May 17, 1900, in which hardly a dozen pine 

 ti"ees in the woods adjoining lot 4 escaped attack. In the areas of 

 woodland where the insects had finished their work the trees cast no 

 shade and appeared to be dead. In places where the larvsB were 

 feeding their dropping excreta made a continuous patter like that of 

 falling rain. From the infested district 34 birds were collected, com- 

 prising the following species: Great crested flycatcher, wood pewee, 

 blue jaj', crow, scarlet tanager, red-eyed vireo, white-eyed vireo, 

 magnolia warbler, black-poll warbler, oven-bird, chat, Canadian war- 

 bler, redstart, gray -cheeked thrush, and olive-backed thrush. Seven 

 birds, including the black-poll warbler, the red-eyed vireo, and the 

 gray -cheeked thrush, had eaten the insect. Since it has not yet been 

 found practicable to protect forest trees by means of insecticides, such 

 services as birds render among these pests ought to be appreciated. 



Plant-lice. — The fact that plant-lice are not selected by birds has 

 been mentioned in the notes on the pea plant-louse. It was illus- 

 trated in the case of a large plant-louse (Ldbchnus) that was noticed 

 on an old willow in the hog-lot gully August 23, 1896. The tree 

 was infested by so many of the insects that its limbs were more 

 or less covered with the honeydew that exuded from their honey 

 tubes, but none of the numerous birds of the neighborhood manifested 

 the slightest interest in the matter. 



Locust Leaf-mining Beetle. — In the summer of 1895 a destructive out- 

 break of the locust leaf -mining beetles ( Odontota dorsalis) turned all 

 the locusts of the farm as brown as if they had been scorched by fire, 

 ruining the verdure of the river bluff. On July 30, 1895, when adult 

 beetles were swarming on the locusts of the hog-lot gully, catbirds 

 were observed to be spending a good deal of time amid the browned 

 foliage. Thirteen were collected and nine were found to have eaten 



