244 MAINE AGRICULTURAL EXPERIMENT STATION. 1907. 



that normally the winter host plant would be sought previous- 

 to the appearance of the males and oviparous females. 



The objection that such forced conditions might have no 

 bearing upon the normal development in the field might be a 

 legitimate one except for the observations taken as a check 

 upon material during this same time that had the liberty of the 

 whole insectary and a choice of host plants. These observations 

 are as follows : 



August 16 about 80 perfectly healthy potato plants in the insectary were 

 stocked with N. solanifolii collected at Orono and were left uncaged. 

 By August 30 they were fairly represented by the photograph (Fig. 26) 

 taken at that time. Later the stalks in most cases died to the ground 

 and new shoots started up from the base. By planting potatoes in the 

 insectary often the plant lice were kept supplied with fresh plants which 

 were colonized by the individuals which deserted the plants they had 

 rendered sickly. 



August 31, 1907, Houlton, Maine. — In a buckwheat field adjacent to a 

 potato field several colonies of Nectarophora sp. were to be found upon 

 buckwheat tips. They were in all respects discernable by a hand lens the 

 same as N. solanifolii. Both green and pink color forms were present 

 but they were so seriously fungus attacked that by the time even the 

 healthiest of the specimens could be brought to Orono, microscopic 

 examination for comparison with N. solanifolii was unsatisfactory and 

 breeding for winged forms was impossible. 



August 31, 1907, Houlton, Maine. — From shepherd's purse Cap sella 

 Bursa-pastoris Moench. several colonies of Nectarophora sp. were taken. 

 They were not to be distinguished from N. solanifolii by hand lens exam- 

 ination and both green and pink color forms were taken. They were 

 badly attacked by fungus and by the time they reached Orono they were 

 in no condition for further observations. 



The suggestions given by these two collections was acted upon con- 

 versely, however, by sowing buckwheat among the potato plants in the 

 insectary and transplanting about 200 young and clean plants of shep- 

 herd's purse into trays. Peas were also sown at the same time. By 

 the time the buckwheat and peas were well up about 100 fresh potato 

 plants were available, and the N. solanifolii, deserting the older potato 

 stalks, colonized thoroughly the fresh potato vines, pea vines, and the 

 shepherd's purse apparently with no preference. Both winged and wing- 

 less forms were found for the rest of the season rearing contented 

 progeny upon potato, and shepherd's purse, and also upon the young pea 

 vines until they killed them. Except for stray individuals which, of 

 course, would be found upon everything in the crowded insectary, the 

 buckwheat remained apparently untouched. Whether iV. solanifolii 

 would have accepted the blossom tips of the older buckwheat or not was 

 not demonstrated as the buckwheat, although it lived, did not make much 

 growth. 



