302 MOSQUITOES OF NORTH AMERICA 



a nearby ship were also stricken. Yellow-fever mosquitoes were found on the 

 ship but apparently there were none on shore and the disease did not spread. 



A short account of the importations and outbreaks of yellow fever which have 

 occurred in past years in Europe is published by Dr. J. M. Eager in a series of 

 pamphlets of the Yellow-Fever Institute (U. S. Marine-Hospital Service) Bul- 

 letins Nos. 3, 4, 5 and 8. All are traced to vessels coming directly from the 

 West Indies or South America. In many instances (all of those in Great 

 Britain) the cases were confined to members of the crews of the vessels, the 

 climatic conditions having been unfavorable to the propagation of the disease 

 and the necessary species of mosquito absent. In the cases where there was an 

 outbreak, as in ports in Italy and southern France, these are exactly comparable 

 to the outbreaks that have occurred in former years in the northern cities in the 

 United States. They were summer outbreaks, ceasing on the appearance of 

 winter, and started by the carriage of infected mosquitoes, or the arrival of 

 persons in the infective stage of the disease at a suitable season from regions of 

 permanent establishment. 



Some recent very interesting observations have been made in the actual carry- 

 ing of living calopus from Brazil to Europe, and the conditions under which 

 they will exist in two portions of Europe have been studied. 



Otto and Neumann, in their account of their expedition to Brazil under the 

 auspices of Hamburg merchants, to study the sanitary conditions of the Bra- 

 zilian ports, brought back with them to Hamburg living adults of calopus which 

 they fed on the journey from a canary and from white rats. On arrival at Ham- 

 burg they found that even in the summer time calopus is not able to breed in 

 the open air for a full generation, although they succeeded in breeding them at 

 an artificial temperature of 27° C, and also in the ordinary temperature of the 

 houses. They found that cold killed them rapidly. At zero (C), they died 

 instantly ; at A° they lived only an hour, and lived for 82 days at a temperature 

 of from 7° to 9°. They found that eggs preserved dry did not hatch after eight 

 days. When they were kept at 27° they would still, at the end of twelve days, 

 give birth to larvae. As with the eggs, the perfect insects live longest at an 

 even temperature of about 27°. 



Marchoux and Simond brought calopus adults with them from Brazil to 

 France. They took 20 females and 20 males, isolating them in rearing tubes 

 immediately after their transformations on the 15th of February some time 

 before their departure from Eio. During the voyage they were fed on glucose. 

 On arrival in France the 5th of May, 17 females and 9 males were alive. In 

 France they reared five generations at the ordinary temperature, the eggs of the 

 last hatching in September. The larvae of this last generation lived until the 

 middle of October without transforming. Some of them, however, gave perfect 

 insects a little later, and these were kept until the 10th of November by feeding 

 on glucose. One female of this generation, taking a meal of blood, laid 60 eggs 

 which did not hatch. All adults died early in November. 



This experiment, carried on through six months of the warm season of the 

 French climate, showed that the yellow-fever mosquito can breed for four or 



