JUAN VINAS— TENANTS OF BROMELIADS 237 



caught. Around bromeliads of a different species two fe- 

 males of M. modestus were fluttering and alighting, and 

 although we did not see them making any motions of ovi- 

 position one of them disappeared into the leaf-bases as if 

 she might be on such an errand. On the outside of one of 

 the yard-long leaves, about six inches from the apex, was a 

 shed larvae skin which we secured. On May i a female 

 of modestus was transforming on the outside of a leaf on 

 this latter cluster and P. secured both her and her exuvia. 

 These observations show that in spite of unnatural sur- 

 roundings and perhaps lower temperature our larvae at 

 Cartago were not retarded in their development as compared 

 with their free relations in their native forest. 



After our return to the United States Mr. Knab sent us 

 the fragments of the two dragonilies which he bred from 

 arboreal bromeliads. These fragments, of adults which had 

 transformed at Cordoba, Mexico, in April, 1908, proved 

 to be also Mecistogaster modestus. 



The origin of the bromeliadicolous habit of the larvae 

 of Mecistogaster modestus may possibly be accounted for 

 in the following manner. The majority of the species of 

 Mecistogaster are South American and some of them occur 

 along the Amazon, where also are the headquarters of the 

 Bromellaceae. As Is well known, "thousands of miles of 

 forests" along this river are inundated each wet season, 

 so that a person "will travel through this forest for days, 

 scraping against tree-trunks and stooping to pass beneath 

 the leaves of prickly palms, now level with the water though 

 raised on stems forty feet high" (Spruce, Wallace). At 

 such periods of high water, epiphytes, whether of the Brome- 

 llaceae or of other families, would often be just at the water's 

 surface, or only slightly submerged, and would offer to drag- 

 onflies quite ordinary and usual places of oviposltlon. An 

 association with certain plants might thus be formed by 



