79 



The period of flight of the winged insects in the present year was 

 very long, having continued a full month from September 14 to Octo- 

 ber 15. After the middle of October I found no winged insects and no 

 nymphs. All that time the weather was warm, and in the sunny days 

 it was easy to observe the conveyers [of the pest?| possessing well 

 developed wings and flying over the twigs of healthy as well as infested 

 apple trees ; on the latter I found the winged louse also sitting at the 

 injured places among colonies of sucking wingless lice, and also on the 

 lower side of the leaves of the apple tree on which the winged louse 

 feeds by making holes in them and sucking them. 



On the 14th of September, while riding from Sebastopol to Simphe- 

 ropol, I caught some winged lice on the window panes of the car. 

 Another time, on September 28, while looking over apple trees on 

 which no wingless blood lice were found, in one orchard near the vil- 

 lage Biel, on the Alma, I observed many living and dead winged lice 

 hung up in the web woven by a spider on the twigs of the trees at 

 the height of 7 feet. The nearest infested orchard was situated some 

 850 feet (about 0.165 of a mile) from the place mentioned, and the 

 winged louse flew over that distance. Later I repeatedly found winged 

 blood lice entangled in webs on such trees where I could not discover 

 any infection by the wingless lice. 



In observing the flight of the blood louse in the room under a glass 

 bell jar I had frequent occasion to convince myself that the louse uses 

 well its organs of flying, and is especially lively at noon in the sun. 

 Notwithstanding the ability of the winged louse to make comparatively 

 long flights, it appears, however, a bad conveyer of its offspring to new 

 places. This will be understood from the following observations: 



On the 19th of September I cut off some shoots of an apple tree which 

 were strongly infested by the blood louse, placed them in a vessel with 

 water, and covered them with a glass bell jar. After three days I 

 noticed two winged lice, which I placed on a cover glass. ( ?) On the 

 following day they gave birth to eleven sexual individuals, among 

 which one was a male, while the others were females. 



After that, on every following day to the end of September, more 

 and more lice assumed the winged state under the bell jar. I trans- 

 ferred them to the cover glass ( ?), and on a small apple tree planted 

 into a flower pot and covered by a bell jar. On the lower side of the 

 the leaves the winged females gave birth (the embryos came in the 

 world with the posterior end of the body forward), usually on the sec- 

 ond or third day, to seven sexual individuals, on the average. The 

 winged individuals live as much as a week, but the bringing forth 

 of sexual ones stops on the third or fourth day after the assumption of 

 the winged state. 



Of the great number of the sexual individuals seen by me the greatest 

 majority were females ; to five, sometimes even to ten, females there is 

 only one male, 



