June, 1906.] KNAB: GOELDl'S " Os MOSQUITOS NO PARA." 65 



species has become completely domesticated. While certain species 

 of mosquitoes probably persecute by preference particular animals, 

 among all the mosquitoes there is none that has so exclusively adapted 

 itself to the persecution of man in the tropics as Stegomyia fasciata. 

 Along the Atlantic littoral of South America it fastens upon the heels 

 of man wherever he settles in numbers and the houses are concentrated 

 into cities of any size. Steam navigation has been the means of 

 spreading the species, and only by taking into account this fact can 

 its present geographical distribution be understood in its details. A 

 valuable illustration is furnished by the manner in which Stegomyia is 

 little by little conquering the Amazon valley. It has departed, by 

 exception, from the littoral route, and entering in a perpendicular di- 

 rection to the coast line, has reached the remote interior. It has 

 established itself at Manaos, capital of the state of Amazonas, a rap- 

 idly growing city of modern aspect 1,600 kilometers from Para. 

 However, according to reliable information obtained by the author, 

 the species has not made itself felt in Santarem, Faro, Monte Allegre 

 and Obidos, all cities at a much lesser distance from Para. The 

 author thinks that while there may be other secondary factors, the 

 principal reason for this negative condition is the small size of these 

 towns. The author believes that an inquiry into the data when 

 yellow fever first appeared at Manaos, and the beginning of steam 

 navigation with Manaos as a terminus, would show an intimate and 

 significant relation between these two facts. The great waterway, 

 with its direction nearly parallel to the equator, navigable for large 

 ocean vessels to its upper reaches and with its climatic conditions most 

 favorable to this eminently tropical mosquito, will prove an excellent 

 highway in the conquering march of 'Stegomyia. Even while the sheets 

 were in press, the newspapers of Para brought telegraphic notice that 

 the " black vomit " had made its appearance in Iquitos (Peru) on 

 the upper Amazon. In Para, in certain parts of the city, Stegomyia 

 abounds to the point of making existence unbearable, particularly for 

 those whose professional duties keep them at the work-table. The hot 

 hours of the day are those in which it shows itself most blood thirsty 

 and insistent. When one perspires slightly it persecutes by its bite 

 with a tenacity and cruelty of which it would be hard to find another 

 example. That the growing insolence of its persecutions goes parallel 

 with the increasing perspiration of our body is something which must 

 impress every attentive observer. It is evident that the perspiration of 



