August, 



LEONARD: IDIOCERUS PROVANCHERI 



415 



THE IMMATURE STAGES OF THE BLACK APPLE LEAF- 

 HOPPER (IDIOCERUS PROVANCHERI VAN DUZEE) i 



By yi. D. Leox-\rd, Ithaca, N. Y. 



During the past five or six seasons small blackish homopterous 

 nymphs have been observed on apple twigs brought into the Cornell 

 Insectary during ^larch and April for the purpose of rearing apple red 

 bugs. These nymphs have also been seen during the spring and early 

 summer in large numbers on the leaves of many apple trees about 

 Ithaca, N. Y. It was not, however, until the spring of 1914 that an 

 adult of this species was obtained when it was found to be Idiocerus 

 provancheri Van Duzee. 



Osborn & Ball (1898: 124-125) state that the species of Idiocerus of 

 which the life histories are known are confined to the different species 

 of Salix, Populus and Cratagus. Idiocerus provancheri has been 

 reared abundantly from apple and the nymphs have been found on 

 quince and on pear. It is also stated that the adults of this genus 

 hibernate and deposit eggs in the spring and that the nymphs ''usually 

 mimic the color of some part of the tree upon which they feed and are 

 difficult to detect.'' I. provancheri winters in the egg stage. More- 

 over, the black nymphs are very conspicuous on the apple foliage and 

 twigs and are not protectively colored. They do, however, have a 

 strong resemblance to a small Attid spider. These facts constitute 

 interesting exceptions to the above statements of Osborn & Ball in 

 regard to members of this genus. 



The nymphs feed chiefly on the under side of the leaves and when 

 disturbed are very active dodging about on the leaf or running rapidly 

 along the stem. The effect of the feeding of the nj^mphs on the leaves 

 is a yellow stippling similar to that caused by the apple leaf hopper. 



Idiocerus provancheri has been reared on apple twigs received from 

 Oswego and Newark in New York, from Ridgewood, N. J., and Phila- 

 delphia, Pa. Nymphs have been observed on apple trees by Professor 

 C. R. Crosby at Stuyvesant Falls, Williamson, Spencerport, Holley 

 and Penn Yan in New York, by Mr. H. H. Knight at Batavia, N. Y., 

 by Mr. C. B. Savage at Kinderhook, N. Y., by Dr. Robert Matheson 

 at Wolcott, N. Y., and by the writer at Honeoye Falls and Rochester 

 Junction, N. Y. They have been received from Babylon, Long Island, 

 N. Y. Nymphs have also been seen by Professor Crosby on pear at 

 Stuyvesant Falls and by the writer at Oswego, N. Y. 



The seasonal life history has not been worked out but nymphs which 

 had recently hatched were observed in abundance at Stuyvesant Falls, 



^ Contribution from the Department of Entomology of Cornell University. 



