384 A YEAR OF COSTA RICAN NATURAL HISTORY 



the experiment myself; the pulp was sweet and pleasant- 

 tasted, not astringent. The next day I bought three mara- 

 fions {Anacardium occidentale) for five centimos at the eating 

 stand at Atenas station, where they were sold as season- 

 able fruit. Each was about three inches long, the pulp 

 making two inches, the stone one inch, of the length. The 

 pulp was yellow and covered with a red or yellow skin, 

 the red almost of the tint of a less "bricky" tomato. Its 

 odor suggested the anona; its taste was very acid, astringent 

 and somewhat sweet. The hard stone which hangs below 

 the fleshy receptacle was pale purplish-gray externally. 



Having learned the dwelling place of Thaumatoneura 

 larvae on the Atlantic side of Costa Rica, it seemed as if 

 they or a similarly-constituted species should live in similar 

 situations — more or less vertical rock faces in running or 

 falling water — on the Pacific slope. To obtain data on this 

 point I went on the morning of April 13 to the Quebrada de 

 Salas, south of the railroad, where it descended steeply 

 to the Rio Grande canon. The white flowers of a guapinol, 

 a mimosaceous tree, overhung the spot but out of reach. 

 Dragonfly larvae were in the swiftly flowing water, but not 

 of Thaumatoneura, nor did they possess any of the peculiar 

 features of its caudal appendages. They were chiefly of 

 a species of Argia, recalling at first sight Argia talamanca, 

 the associate of Thaumatoneura in the waterfalls of Juan 

 Vifias. But on comparison they prove to have the caudal 

 gills proportionally and absolutely longer and more expanded 

 than those of talamanca, although not as slender as those 

 of Argia extranea from the vicinity of Cartago, or as thin 

 and leaf-like as those of Argia larvae dwelling in the less rapid 

 parts of streams in the United States. There was also a 

 larva of Archilestes grandis there, with thin oblong gills, 

 three-eighths of an inch long and rounded at the tip; in 

 short, nothing which at all closely approached the modifica- 



