26o A YEAR OF COSTA RICAN NATURAL HISTORY 



These bracts are so shaped that they can hold an ounce or 

 so of water. When I examined several inflorescences on 

 March 25, 1910, I found in each bract two or more mosquito 

 larvae or pup^e and in some other quite different dipterous 

 larvae also. Some of these mosquito larvae were eventually 

 carried to Philadelphia alive in a vial and, although nothing 

 was given them for food but merely the supply of water 

 maintained, they transformed to the adult stage on May 31, 

 1910. Some of these larvae and a pupa were identified by 

 Mr. Knab as JVyeomyia pa7itoia. They therefore belong to 

 the same genus as the mosquito {JV. smithii) whose larvae 

 breed in the water contained in the pitchers of the pitcher 

 plant (Sarracenia) of the United States. The larv^ of fF. 

 smithii are known to be able to withstand fasting for long 

 periods. Larvae of other species of JVyeomyia live in the 

 water between the leaves of bromeliads or in bamboo joints 

 in tropical America. The adult W. smithii is believed not to 

 suck blood, but of fV. grayii of St. Lucia and other West 

 Indian islands, Theobald reports that it "bites with great 

 readiness and pertinacity." Busck, who studied mosquitoes 

 in Panama, says, "The species of the genus JVyeomyia . . . 

 are among the few day-biting mosquitoes and are decidedly 

 noxious where they abound . . . are very persistent biters 

 during the day-time." Heliconias, bromeliads and bamboo, 

 therefore, offer a breeding place to mosquitoes which annoy 

 man. 



Behind Peralta station (that is, west) the forest began 

 within a few hundred feet of the railroad. An ascending road 

 led into it, which I followed for some distance on August 7, 

 and then turned aside on the first path to the right. Im- 

 mediately I was in the midst of a thick forest of very tall ex- 

 ogenous trees and many palms, from both of which hung 

 clumps of ferns and lianas binding the trunks and branches 

 together. The soil was damp and, in places, deep mud. 



