JUAN VINAS— TENANTS OF B ROM ELI ADS 239 



bromellad and the leaf next without decreases downward 

 and If Mecistogaster^s eggs are deposited In the plant tissue 

 in or near the contained water In accordance with the habit 

 of Zygopterous dragonflles, it would often be necessary for 

 the female to reach far down into crevices possibly too nar- 

 row to admit of the entrance of her thorax and wings. The 

 long abdomen with the ovipositor near its hind end would 

 therefore be of distinct advantage and It will be a matter of 

 great Interest to ascertain, by future observations, if the 

 lengths of abdomens seen In various members of the Anor- 

 mostlgmatlni are correlated with peculiarities In length In 

 the plants or other objects In which they oviposit. 



The abdomens of the males of the species of Mecistogaster 

 are as long as or longer than those of the females. Their 

 length of course cannot be explained in the way suggested 

 for the females, but is possibly due to the necessary correla- 

 tion In length which must exist between the two sexes to 

 enable them to assume the characteristic mating position. 



In describing our discovery of these peculiar dragonfly 

 larvae we have Incidentally mentioned some of the other ani- 

 mals which were living in the bromeliads. In addition to 

 the plants of this family examined at Juan VInas, La Emilia, 

 Cachi, Cartago and the crater of Irazu also furnished in- 

 teresting bromelladlcoli, although none of the dragonfly 

 group. The favorable character of bromeliads as shelters, 

 or as sources of food, for animals Is Indicated by the fact 

 that the cluster from one height on a tree at Juan VInas, 

 which has been designated the "fourth bromellad" yielded 

 25 species associated at one and the same time, although 

 one of these species was an external parasite on the body 

 of a beetle. These 25 species were distributed among the 

 following groups: Insects: 18 species (of 15 genera, of 14 fam- 

 ilies, of 7 orders, Orthoptera, Odonata, Heteroptera, Cole- 

 optera In the majority with 11 species, Lepidoptera, Hymen- 



