144 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



growth of buckwheat planted for winter protection. The plot had 

 been infested with leaf hoppers earlier in the season, and a few were 

 doubt of their being those of the same species. 



All these "blisters" or pouches containing eggs were found on old 

 wood in the upper part of the trunk, and none on the small twigs, and 

 their general shape varied from that of a fresh water mussel or clam 

 shell to almost cylindrical. 



sues. The sap was just beginning to run and the tissues were full 

 of it." 



Of course, it yet remained to be proven that the above egg was that 

 of Empoasca. No more eggs were found until May 24th, when ]Mr. E,, 

 L. Webster, in charge of the insectary and a part of the field work for 

 the department during the summer, found them quite numerous in 

 three-year old apple stock in a southern Minnesota nursery. He re- 

 ports these eggs as being somewhat smaller than those found at St. 

 Anthony Park, measuring .4 and .75 mm. Mr. Ainslie's description 

 applies so well to the later found eggs that there is but little if any 

 still in evidence. Every portion of the bark of several trees was 

 examined most thoroughly with a hand lens without result, but on a 

 few petioles slight discolorations, accompanied in each case by an ele- 

 vation of the epidermis, were found. These were so small that they 

 were hardly visible to the naked eye, and were for the most part lo- 

 cated on the side of the petiole, and on the half nearest the leaf. One 

 was found on the under side of the mid-rib. Empoasca larvae were 

 found on the above trees, and the spots on the petioles were, according 

 to Ainslie, the only abnormal thing about the trees. 



The buckwheat growing amongst these trees was also examined, and 

 two similar discolored swellings found on petioles. At this date there 

 were very few Empoasca on the trees, but they were numerous on the 

 buckwheat. Dissection of some of this material on November 9, pre- 

 served in alcohol since September 19, and not in very good shape, dis- 

 closed nothing of which we can speak definitely. 



Insectary records of the stages of Empoasca show a record of from 

 nineteen to twenty-five days as nymphs, and five nymphal stages be- 

 tween egg and adult. It was practically impossible for us to deter- 

 mine the length of each instar exactly, but it may be safely said that 

 the first brood nymphs have longer instars than those in the follow- 

 ing broods. The average lengths of individuals in the successive 

 nj^mphal stages are as follows : First stage, .8mm. ; second, 1.3 mm. ; 

 third, 1.7 mm. ; fourth, 2.1 mm. ; fifth, 2.4 mm., and the adult 3.1 mm. 



Mr. "Webster reports observing these hoppers hopping in the last 

 nymphal stage, in several instances leaping a distance of over a foot. 



