242 maine agricultural experiment station. i907. 



Insectary Observations. 



During the summer of 1906 this species was bred in the 

 insectary upon potato, but as various other species were under 

 observation in the same house and as two species of the genus 

 Aphis colonized the potato there to an extent which inter- 

 fered with the work with N. solamfolii, little reliable data was 

 obtained. For the season 1907 particular precautions were 

 taken. During the entire summer no plants were grown in 

 the insectary except such as were started there from seed — 

 that is, no risks were taken as to the introduction of any other 

 species of plant louse upon plants. A single exception was 

 made when the house was stocked with shepherd's purse, but 

 for this purpose very young plants were used and these care- 

 fully examined. It should be stated that during the entire time 

 of the observations upon these plant lice the insectary was not 

 heated in any way, so that the temperature conditions were not 

 so widely different from those out of doors, that this element 

 need come in for consideration. It was, however, possible for 

 the insectary colonies to breed unchecked by rains, predaceous 

 or parasitic insects, though a fungus parasite was introduced in 

 August which seriously interfered with the uncaged material. 



The few specimens obtainable (see field notes for Houlton, 

 July 18, 1907) were placed upon potato plants in cloth cages 

 in the insectary July 19; July 22 they were increasing rapidly, 

 many had molted and all seemed healthy. Some such interest- 

 ing data were obtained from the material started at this time 

 that quotations from notes made upon them are here included. 

 These specimens and their descendants, caged in cloth cages 

 from July 19 to September 20, were protected during the entire 

 time from the fungus which was introduced in August with 

 uncaged material and which spread through the insectary. 



August 3, 1907. Insectary. — The progeny of the wingless viviparous lot 

 taken at Houlton July 18 are winged viviparous forms. The stalks this 

 lot have been colonizing since July 18 are speckled with beak wounds. 

 The plants have a general unhealthy appearance and the leaves are sticky 

 with honey dew and somewhat attacked by honey dew fungus. 



These winged individuals left the sickly potato stalks upon which they 

 had fed during the earlier stages of their lives and rested upon the cloth 

 sides of the cage which confined the potato. These winged forms were 

 removed from the cloth and placed in lots of 20 each under cages upon 

 fresh potato previously uninfested. They settled at once, remaining. upon 

 the fresh stalks. 



