96 A YEAR OF COSTA RICAN NATURAL HISTORY 



here and we obtained its larvae clinging to the submerged 

 stems of plants growing on the bank. 



We visited many different parts of the Reventado, par- 

 ticularly above the town on the slopes of Irazu. As the 

 stream had cut little ravines and gorges for itself in many 

 places, it was not always possible to keep at the water's 

 edge so that sometimes we followed its course at the top of 

 the ravine, sometimes on its banks. In one of the potreros 

 above the Reventado we took Gomphoides ambigua on De- 

 cember 15; this is a Gomphine dragonfly not previously 

 known from Costa Rica, although we also obtained it from 

 San Jose and from the peninsula of Nicoya. The little river 

 was often heavily shaded with big trees, with undergrowth of 

 ferns and caladiums, tradescantias and mosses. A partic- 

 ularly charming bit was evidently the bed of an extremely 

 old crater, roughly elliptical in shape with high steep walls 

 except on the south side, and containing many fine large 

 trees. The current here was swift and the stream was poor 

 in dragonflies. On May 24 A. obtained a stone-fly and two 

 stone-fly exuviae, small may-fly larvae, a couple of species of 

 caddis-worms, a galgulid ("toad-shaped bug") — all similar 

 in general appearance to forms in the eastern United States. 



On the same day some Ithomiine butterflies, Hymenitis 

 oto (with clear transparent wings spreading two and one- 

 eighth inches, whose margins and veins are blackish, and 

 with an oblique milky-white band and milky-white spots 

 on the front wings) and Dircenna klugii (already mentioned 

 in Chapter V) were found only in dark shady spots in these 

 woods. The transparency of their wings made them much 

 more difficult to see, whether in flight or at rest, than other 

 butterflies whose wings were of the normal style — colored 

 and not transparent. Dr. Sharp, in the Cambridge Natural 

 History (Vol. VI, p. 346), quotes Wallace briefly as making a 

 similar observation on these butterflies. However on Mav 



