TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. 23 



Fourth instar. — General color light yellow. Eyes almost pearl white with a brown 

 central spot underneath. Wing pads extending to hind margin of the second abdom- 

 inal segment. Spines very distinct. Average length of 16 specimens 2.03 mm. 



Fifth instar. — General color as in previous stage. Eyes almost pearl white. Wing 

 pads extending nearly to the hind margin of the fourth abdominal segment. Broader 

 than in previous stage. Average length of 16 specimens 2.85 mm. 



THE ADULT. 

 PI. V, A, C. 



General color of adult creamy white to light yellow. Head rather pointed, pale 

 yellow; face of male with a tint of orange color in the form of a central longitudinal 

 stripe with several transverse radiating stripes; gense pale, narrow, and almost as long 

 as clypeus ; lorae very narrow, sunken beneath the compound eyes. Vertex pale yellow 

 with two semi transparent spots just above the ocelli, a faint median longitudinal 

 semitransparent line extending from the hind margin half-way to the front margin, 

 and a semitransparent line bordering each eye. Two ocelli present, situated on the 

 frontal margin of the vertex, marked by two white spots with a dark center, distance 

 apart twice that from the eye to the ocellus; eyes pearl white with a darkened center, 

 ashen-gray after death. Pronotum light yellow with a semitransparent area in the 

 center; mesonotum semitransparent with a large trapezoidal creamy area extending 

 from the front to the hind margins, wider behind; a small cream colored area anteriorly 

 on each side; scutellum cream-colored, sometimes with a semitransparent area caudad. 

 Elytra transparent. First two segments of antennae pale, flagellum dusky. Legs pale, 

 tarsi dusky at tips. Sexual appendages slightly ciliated in female only. Average 

 length of 12 specimens 3.00 mm. 



LIFE HISTORY AND HABITS. 



The Egg. 



Part of the rearing work in the life history of the rose leafhopper 

 was conducted during the spring of 1915, the work being completed 

 during the season of 1916. In obtaining data on the biology of this 

 insect the same methods as devised for the study of the apple leaf- 

 hopper were used. 



Winter egg. — This leafhopper hibernates in the egg stage, winter 

 eggs being deposited in the fall during the period extending from 

 the last week in September to November 1. They are laid almost 

 entirely under the bark of apple trees and rose bushes, though a few 

 have been found in pear, quince, cherry, plum, currant, and Cra- 

 taegus. The eggs are deposited singly, usually lying hi a longitu- 

 dinal position just under the epidermis, and they are placed in a dis- 

 tinct blister or pouch which measures 0.7 to 0.8 mm. in length. 

 They are easily located by looking on the bark for the raised blister, 

 which, as a rule, is slightly crescentio in outline. Winter eggs have 

 been found in the bark of nursery apple trees from one to four years 

 old; they are found in greatest numbers on the first year's growth of 

 two-year trees. The favorite location for oviposition seems to be 

 around the bases of the lowest limbs or on the trunk just below the 

 first branches. 



