POTATO PLANT LOUSE. 24 1 



nearly so many on my vines as I did a week ago. The blossoms are 

 about all gone from my potatoes and the small stalk on which the blos- 

 soms grew is a dirty brown color and seems to be withering up." 



August 17, 1905, Houlton. — The writer found N. solanifolii excessively 

 abundant over about 20 acres. The stalk tips were crowded with 

 viviparous forms both winged and wingless, and in many cases the flower 

 stalks were dead. 



August 25, 1906, Houlton. — Potato stem tips and leaves literally packed 

 -with N. solanifolii. Much injury to the potato tops evident. 



July 18-19, 1906, Houlton. — A 2 days' careful search in 4 large potato 

 fields (one of which is the field for which the foregomg record of August 

 17, I 9°5 ! is made) resulted in the finding of but one specimen of N. 

 solanifolii. That single specimen was a wingless form and there were 

 3 lady-beetles after it. 



July 18, 1907, Houlton. — A large field that had been heavily infested 

 the previous August was examined. A very few scattered individuals 

 were found on the blossom stalks of potato. A most thorough search 

 for some distance over many rows revealed not more than an average of 

 a single specimen to 3 rods. These were wingless viviparous forms 

 sometimes apparently still too young to start a colony and sometimes 

 mature and accompanied by a very few progeny. No winged form was 

 seen on this date. 



July 24, 1907, Kennebunkport. — N. solanifolii present upon potato but 

 very scattering and chiefly wingless. A single winged specimen taken. 



July 25, 1907, Farmington. — A 7 ", solanifolii present upon potatoes but 

 very much scattered. 



July 31, 1907, Houlton. — (Same field as foregoing record for July 18, 

 1907). N. solanifolii nowhere numerous, yet preser* all over the field. 

 A single wingless, viviparous form with progeny ( i every third and 

 fourth hill and winged viviparous forms with proge. y found here and 

 there, but less common than the wingless forms. A few individuals 

 whose wing pads indicated they were but one molt from maturity taken 

 on this date would indicate that these winged forms present did not 

 come as migrants but had developed as progeny of the wingless forms 

 noticed earlier in the month. 



September, 1906, Houlton. — Early in the month the fall migrants 

 acquired wings and deserted the potato. On September 14 only 4 or 5 

 belated specimens were found in a day's search in several fields where 

 the infestation had been excessive in August. No males or oviparous 

 females were seen upon the potato in the field during the 3 years though 

 frequent searches were made. Although the infested fields were visited 

 once or twice weekly for nearly the entire season, further quotations from 

 the field notes for 1907 are omitted here because on account of continu- 

 ous and heavy rains the species were held much in check and also because 

 later practically the whole infestation was killed out by a fungus parasite, 

 the natural increase of the species being prevented by either cause enough 

 to make the field notes for the present year exceptional rather than the 

 rule. 



