449 



NELSON C. DAVIS AND RAYMOND C. SHANNON. 



In May, 1926, Shannon and Paterson found A. rondoni at Calilegua 

 (about six kilometers from Ledesma), Province of Jujuy. In March, 

 1927, it was found again in this same región by Shannon and Del Ponte. 



BrEEDING PLACES. 



Although the first A. rondoni bred out by us in August, 1925, carne 

 from the edge of a reservoir (water dammed up for irrigation), this 

 focus was later found to produce a great predominance of A. pseudo- 

 punctipennis. (See Fig. 1.) However, a shallow ditch at the margin 



FiG. 1. Reservoir near Cañitas, Ledesma, Province of Jujuy. Found breeding 

 A. rondoni in August, 1927, later found to produce a predominance of A. pseudo- 

 punctipennis. 



of a reedy swamp behind the reservoir was a breeding-place highl}^ 

 favored by rondoni. (See Fig. 2.) This ditch was connected with the 

 adjacent swampy lake but presented a different flora; its margins were 

 grassy, the water was fairly clear, there was a certain amount of 

 detritus present, but no visible algae. On the other hand, the swamp 

 contained cat-tails, supported a profuse growth of green algae and 

 bred A. pseudopunctipennis. 



From a collection taken in the ditch on March 2, 1927, 100 con- 

 secutive larvae were examined. Of these, 98 were of the tarsimacu- 



