EXPERIMENTS ON BITING HABITS 265 



The conclusions of the commission rest, at least in the main, upon the observa- 

 tions of one of the members who was detailed for this work, A room was pre- 

 pared to serve as both laboratory and sleeping room, arrangements made to pre- 

 vent the escape of mosquitoes, and here the observ^ations were to be made under 

 the most natural conditions possible. " L'un de nous s'est astreint a habiter 

 cette piece pendant la joumee et la nuit, afin d'observer les Stegomyia fasciata 

 qui, soit isolement, soit par series, y ont ete introduits au cours des saisons 

 chaudes de 1904 et 1905, dans un but experimental." * (Ann. Inst. Pasteur, 

 vol. 20, 1906, p. 105.) We are further informed that the observer absented 

 himself from the room at meal-time only and that the observations were con- 

 tinued day and night, the first time during 18 days, the second time during 28 

 days. Clearly a continuous effort for such periods is beyond the power of the 

 ordinary man and the excessive fatigue resulting from such an attempt must, 

 as we shall see, seriously affect the character of the observations. 



Seven separate experiments were made. Five of these were with series of from 

 6 to 8 mosquitoes and two of them were with single mosquitoes. Thus 42 is the 

 maximum that we can assume of mosquitoes used in these experiments. Five 

 of these experiments were cut short before the sixteenth day by the accidental 

 death of the mosquitoes. In the two remaining experiments, which were carried 

 beyond the sixteenth day, nine mosquitoes were employed. The results of these 

 two experiments are given in detail ; of the others we are briefly told that the 

 results were similar, as far as the biting habits are concerned. " Nous rap- 

 porterons en detail les deux dernieres comme etant les plus completes." (We 

 report in detail the two last as being the most complete.) 



Experience I. 



Un lot de 8 Stegomyia fasciata femelles, nees et elevees au laboratoire, sont 

 mises en liberte dans la chambre a experience, 24 heures apres leur passage a 

 Fetat parf ait. Pendant ces 24 heures elles sont restees enf ermees en compagnie 

 de males et ont ete vraisemblablement fecondees. 



le jour : piqures nombreuses entre 9 heures du matin et 5 heures du soir. 



2e Jour: piqures (1 ou 2 seulement) entre 3 et 6 heures du matin, a I'ob- 

 scurite. Piqures nombreuses de 10 a 11 heures du matin. 



3e jour: piqures entre 1 et 5 heures du matin. 



4e jour : piqures entre 9 et 10 heures du matin. Piqures entre 4 et 5 heures 

 du soir. 



5e jour : piqures a 5 heures du soir. Piqures a 10 heures et -| du soir. 



6e jour : piqures entre minuit et 5 heures du matin. Une piqure a 3 heures 

 du soir. 



7e jour : piqures a 5 heures | du soir. Piqures a 10 heures du soir. 



8e jour : piqures a 2 heures du matin, a I'obscurite. 



9e et lOe jour : pendant ces 2 jours, on a laisse les moustiques seuls dans la 

 chambre a experience. 



lie jour: piqures entre 6 heures et 6 heures -J du soir. Piqures entre 10 et 

 11 heures du soir. 



* " One of us was obliged to inhabit this room day and night in order to observe Stegomyia 

 fasciata which, sometimes singly, sometimes in series, were introduced, during the hot seasons 

 of 1904 and 1905, for experimental purposes." 



