Insects at Rebecca Shoal and Tortugas. 201 



were taken in the act of biting some person. During a flight it was 

 necessary only to station one's self quietly in the windward door of a 

 room in order to entice any mosquito present within reach of the net. 

 After it had been observed that these insects occasionally were at- 

 tracted to the corks of bottles of raspberry shrub, dishes containing 

 some of the liquid were set in several likely positions. Examination 

 now and then resulted in the capture of a mosquito. After dark a 

 flash-light was of great service in locating mosquitoes which were 

 attempting to bite. 



In order to capture house-flies it was necessary only to keep a 

 close watch in the kitchen and living rooms and to net those which 

 approached men at work outside. It was found possible to keep the 

 station practically free of Mucsa domestica in this way. During 

 periods of continued easterly winds the larger number of those taken 

 on a given day were captured easily just after daybreak. These had 

 doubtless arrived during the night. Single specimens would then be 

 noted at long intervals during the day. Thus when dusk fell the 

 station would again be practically free from flies. 



It should be stated in this connection that there were absolutely no 

 breeding-places for Musca domestica upon the station. The sewage 

 and garbage were at once committed to the sea. 



INSECTS TAKEN AT REBECCA SHOAL FROM JUNE 26 TO JULY 18. 



Those insects which migrated to Rebecca Shoal light-station proved 

 to belong to four orders, Odonata, Neuroptera, Lepidoptera, and Dip- 

 tera. Of the first order only two appeared, one being a large dragon- 

 fly and the other a damsel-fly. A single Neuropteran, the golden-eyed 

 lace- wing Chrysopa, was taken, while the only Lepidopteran was a 

 moth, Syntomeida epilais Walker. The Diptera, as anticipated, were 

 more numerous both as to species and individuals, and it is with these 

 that the remainder of the paper will be mainly concerned. 



On the next page is a table showing the weather conditions and the 

 kinds and numbers of insects taken. 



Considering first the occurrence of mosquitoes, the table on the fol- 

 lowing page shows that during all the time from June 26 to July 3, 

 while the wind was blowing from the east or changing into the north, 

 only a single mosquito was noted. This was taken on July 1 at 9 p. m., 

 and was of the species Aedes niger. It is probable that its point of 

 departure was the Marquesas Keys, 24 miles to the east. A few 

 others appeared later on east winds. 



On July 2 the wind shifted into east-northeast and continued lightly 

 from that direction during the night. At 5 a. m. of July 3 it was north, 

 having shifted considerably during the night; at 10 a. m. it was north- 

 east, at 12 noon it was north and continued so during the rest of the 

 day, freshening toward night. The weather was now clear and the 

 moon full. No mosquitoes were noted during the day. 



