27 



that mosquitoes came aboard in large-quantities at Vera Cruz, although 

 he lay a half mile from shore and there were variable winds with 

 squalls and rain all the time. The number of the insects decreased on 

 the voyage but were always in evidence, and we caught four or five of 

 them here. No larvae were found in any of the tanks, and as the cap- 

 tain had repeatedly examined them without result in his efforts to be 

 rid of the mosquitoes, I believe the insects found on board here came 

 all the way from Vera Cruz. 



The schooner Eleanor arrived from Vera Cruz on July 17, 1902, 

 thirteen days out. She had no mosquitoes on board before reaching 

 Vera Cruz, but there quantities came on board. Her moorings were 

 half a mile from shore and the winds were variable. The captain 

 stated that he could not get rid of the insects after sailing, although 

 the number decreased very much and there were no larvae in any of 

 the tanks. At the time of her inspection here we caught and identi- 

 ' fied a number of Stegomyia. 



The brigantine John II Crandon arrived at the station July 27, 

 1902, twenty-tWo days from Vera Cruz, where she had one case of 

 yellow fever on board. At that port she lay a half mile from the sea 

 wall, threes-eighths of a mile from an infected prison, and within 200 

 yards of an infected vessel. Stegomyia fasciata were found on board 

 by Acting Assistant Surgeon Hodgson before she sailed, as well as 

 larvae in the tanks. All during the trip there were mosquitoes in 

 abundance, and a veritable plague of Stegomyia was found on board 

 oh her arrival here. There was a constant buzz in the forecastle, and 

 anyone entering was sure to be attacked by several mosquitoes. Spec- 

 imens were caught in almost every protected part of the vessel, and 

 all were found to be the Stegomyia fasciata. The captain had emptied 

 several water barrels because he found they were breeding mosqui- 

 toes, but the water remaining had no live larvae, although many Old 

 moults were seen. As breeding was surely going on in the tanks dur- 

 ing a part of the voyage at least, it would be impossible to say how 

 long any particular mosquito had been aboard or if any of them had 

 been brought here from the infected port. 



SUMMARY. 



The above facts may be summed up as follows: 



Vesssels having no mosquitoes on board at any time 65 



Vessels having mosquitoes on board in port of departure 5 



Vessels on which mosquitoes ( Culex) appeared en route 9 



Vessels arriving with Stegomyia fasciata on board 3 



Three and a half per cent, then, of all vessels brought Stegomyia 

 on a voyage averaging seventeen days. 



