AND OTHER INJURIOUS INSECTS OF I907 AND I908. 



13 



distance of over a foot, when slightly disturbed. The adult hoppers 

 f\y as well as hop, as may be readily seen by shaking an infested nurs- 

 ery tree, causing the tiny insects to leave it, often in clouds. 



The average length of individual nymphs of the first stage is .8 

 mm.; of the second, 1.3 mm.; of the third, 1.7 mm.; of the fourth, 2.1 

 mm. ; of the fifth, 2.4 mm. ; and of the adult, 3.1 mm. 



The length of life of each nymphal stage, as found by Dr. Frank- 

 ling in insectary work in 1908, is as follows: First stage, three to five 

 days ; second stage, one day ; third stage, six days ; fourth stage, six 

 days ; fifth stage, four days, or an average of 

 twenty-two days from egg to adult. These data 

 are the results of one experiment only. The 

 1908 observations are corroborated, as far as the 

 total time is concerned, by the work of 1907. 

 when it was found that the insect spent from 

 nineteen to twenty-five days in the nymphal 

 stages, though Mr. Webster did not, in 1907, de- 

 termine the length of time spent in each stage. 

 The adult mav live at least fourteen days, and 



Fig. 2. Third stage of ^. , ,, , ' ,. • , 



maii, from life, much en- probablv longer, accordmgf to insectary observa- 



larged. Original. . . , r^^o ^t-i i r^/^T • 



tions m 1908. The 1907 msectary experiments 

 indicate that the adult may live more than twice that length of time. 



The Winter Egg: The winter 

 egg, we believe, is laid during the lat- 

 ter part of September in the bark of 

 apple (and other?) trees, its presence 

 being denoted by a blister-like raising 

 of the outer portion of the bark, under 

 which it may be found. Fig. 5 is 

 made from a photograph of an egg, 

 after it had been exposed by careful 

 dissection by Dr. Franklin, and Fig. 

 6 shows a nymph hatched from such 

 an egg. We have been unable to find 

 fall laid eggs in any herbaceous plants, 

 though during the summer many vari- Fie. 3. Fourth or pupai stage of /;. 



.• r 1 ,1 » • Wirt/', from life, much enlarged. Original. 



eties oi such growths are swarming 



with Enipoasca. The egg blisters measure from .7 mm. to .85 mm. 



The egg pockets from which our measurements were made (and 



which we believe to be those of E. niali, because of their resemblance 



to those on nursery stock from which E. iiiali was reared) were 



