THE APPLE LEAF HOPPER AND OTHER IN- 

 JURIOUS INSECTS OF 1907 AND 1908. 



BY F. L. WASHBURN 



TWO YEARS' WORK WITH THE APPLE LEAF HOPPER, 



Empoasca inali LeB. 



Synonyms: Einf>oa albopicta Forbes, Tettigoiiia iiiali LeB., E. 

 albopicfa Woochvorth, Typhlocyba photophila Berg. 



Explanation of colored plate: Figs. 1, 2, 3, 4 and 5 represent five suc- 

 cessive stages of the nymph; Fig. 6, the adult Leaf Hopper; Fig. 7, the 

 newly hatched nymph (summer) issuing from petiole of clover. The cen- 

 tral figure illustrates the appearance of the terminal portion of an apple 

 twig upon which this Leaf Hopper is working. 



SUMMARY OF RESULTS. 



L This insect is at least two-brooded in Minnesota, young nymphs 

 appearing upon apple trees soon after the leaves open, and 

 the last brood of adults ovipositing in the tissues of the bark 

 of apple (and other?) trees. The eggs of the summer broods 

 are laid in the petiole of clover, apple, and doubtless many 

 other plants, which furnish them food during the summer 

 months. 



2. There are five nymphal stages, and the length of time elapsing 



between hatching of egg and appearance of adult averages 

 about twenty-two days. The adult may live fourteen days 

 or over. Experiments of 1907 indicate that thirty days or 

 more may be passed in adult stage. 



3. The presence of the winter egg is denoted by a blister-like swell- 



ing on bark of apple, about .75 mm. long by .4 mm. broad. 

 The contained egg is about as long as the blister, hyaline and 

 semi-opaque. See Fig. 5. 



