78 



"Wisconsin — Continued. 



Sauk— Continued, 

 holes. In the woods near by their noise resembles the distant roar of the 

 sea. Chicago Times-Herald clipping, June 25, states that they appeared at 

 Baraboo a month ago; much more numerous than seventeen years ago. 



Sawyer. — William Powers, Hayward; June 8; few in certain places. 



Washburn. — Andrew Ryan. Shell Lake; June 15; not to any extent. 



Waushara. — H. 0. Kruschk, Aurora ville; June 17; some in western part of county, 

 according to report. 



SOME OBSERVATIONS ON THE CYCLE OF THE SEXUAL DEVELOP- 

 MENT OF THE "BLOOD LOUSE." 



(Schizonetira lanigera Hausni.) 



By S. MOKRZHETSKI.* 



Notwithstanding the fact that ScMzoneura lanigera Hausin. was the 

 subject of numerous observations in various countries, some stages of 

 its post-embryonic development are still insufficiently investigated and 

 their role in the life of the insect is not cleared up. The appearance 

 of the "blood louse*' in great numbers in the Crimea gave me an oppor- 

 tunity last summer to turn my attention to those uncleared-up points 

 in the development of the insect and I shall endeavor to lay down 

 briefly my observations. 



It is Mell known that in the blood louse a double cycle of develop- 

 ment is observed, one with a sexual generation and the other without 

 it, and that after a number of broods of this insect which are born par- 

 thenogenetically from wingless viviparous females — nurses — toward 

 the fall among the wingless male nurses there appear individuals with 

 rudimentary wings, so-called nymphs. 



In the past fall in the Crimea I did not find nymphs before Septem- 

 ber $ on the 12th of September (old style) I found in one garden (on 

 the Kacha) nymphs entirely ready to assume the winged state, and on 

 the llth of September I observed the flying of the winged blood louse. 

 The ability of the winged insect to fly was a matter of doubt in our 

 science. While some investigators (Kessler)t asserted that the winged 

 blood lice move about little and are not capable of spreading the infec- 

 tion on other unaffected apple trees since they are unable to fly over 

 to them, other investigators, among them R. Goethe, ascribed to. the 

 winged insect the ability to fly well and to spread the pest to new 

 places. 



My observations show that the winged blood louse flies well, but is a 

 bad conveyer of the infection to new places. 



* Translated from the Russian by Prof. P. Fireman, Columbian University, Wash- 

 ington, D. C. 



tDr. H. F. Kessler, "Die Entwickelungs und Lebensgeschichte der Blutlaus." 

 CasseL 1.385. By the same author: "Die Ungefahrlichkeit und kostenlose Vertil- 

 gung der Blutlaus 7 ' in the "Bericht fiir Xaturkuude zu CasseL" 1889. 



