April, '12] JENNINGS: MOSQUITO CONTROL IN TROPICS 131 



we secured this species in considerable numbers on the 28th of Sep- 

 tember. 



H. A. Surface : Just one important observation should be recorded. 

 I found them very injurious to Salway Peaches. I found that after 

 the fruit ripened they would insert their probosces, sucking out the 

 fruit in a circle half an inch in diameter and they would also stain 

 the fruit brown, a very serious damage, amounting to many dollars. 



E. N. Cory: I would hke to make a report from the Maryland 

 Station of the occurrence in large numbers of this moth at Adamstown, 

 in Frederick county, and cite a report by a correspondent that the 

 moth was injuring crops, puncturing grapes and feeding on the juices 

 to a considerable extent. We were unable to verify the report. 



President F. L. Washburn: We will have to stop this discussion 

 here, I am afraid. The next paper will be read by Mr. Jennings, on 

 "Some Problems of Mosquito Control in the Tropics." 



SOME PROBLEMS OF MOSQUITO CONTROL IN THE 



TROPICS 



By Allan H. Jennings 



That part of Panama which comprises the Isthmian Canal Zone 

 lies in about 9° of north latitude and is characterized by a typically 

 tropical climate, high humidity, heavy rainfall, and a short dry season, 

 usually lasting not more than four months, sometimes decidedly less. 

 A rich virgin soil is clothed by dense and luxuriant vegetation. Of a 

 hilly, in some parts mountainous topography, it is well watered by 

 numerous brooks, streams and rivers. The climate is equable, the 

 temperature never rising to excessive heights, and the seasonal varia- 

 tion is slight. High winds and violent storms are practically absent 

 and thunder storms, even without wind, are rare compared with their 

 occurrence in the temperate United States. In the rainy season, 

 when well established, precipitation is not constant; the daily rain 

 usually occurs about noon and continues for a longer or shorter period, 

 the nights and mornings being usually clear. The yearly rainfall is 

 not equal in all parts of the Canal Zone; the extremes are noted at 

 Colon and Panama, precipitation being about twice as heavy at the 

 former place as at the latter. While least rain falls at Panama and in 

 the country close to the Pacific coast-line, heavier precipitation begins 

 several miles before the divide is reached at Culebra, and from the 

 latter point to Colon, about thirty-three miles away, the rains are 

 very heavy. 



As is to be expected in a country exhibiting such conditions, the 



