258 A YEAR OF COSTA RICAN NATURAL HISTORY 



ent twig was a wingless walking stick {Ceroys bigibbus) 

 whose color and roughness of body-surface were perfect 

 imitations of the color and surface of a broken twig. The 

 antennae and the first pair of legs were held close together 

 and straight forward in prolongation of the body and did 

 not betray their possessor as did the oppositeness of the re- 

 maining legs, which projected at marked angles. The most 

 interesting feature of the observation to me was that the 

 insect was resting not on a woody stem or branch, where the 

 protection derived would have been greater, but upon the 

 contrasting background of the green leaf. It is not uncom- 

 mon for veritable twigs to fall upon such leaves, but the 

 occurrence of this insect upon the leaf certainly indicated 

 an absence of the power of selecting an advantageous resting 

 place where its "protective coloration" would protect. The 

 walking stick was taken to Cartago and photographed while 

 still alive. 



Coming out of the woods, I stopped at the laguna to dredge 

 for dragonfly larvae, but without success. My brown tin 

 collecting case was lying in the sun on the ground and some 

 patches of black paint, which had been put on five months 

 previously and were thoroughly dried, attracted a number 

 of large brown-winged horse-flies {Pangonia pyrausta) with 

 probosces nearly as long (one-half inch) as their bodies, 

 which were five-eighths inches long. I paid little attention 

 to them at first, but when one of the insects flew again to 

 the box after it was placed in the shade thirty feet or more 

 from its former position, I caught the fly for future identifi- 

 cation. The paint had not softened, so I do not see what 

 the attraction for the insect was. 



On March 23, 191c, I visited the laguna again, crossed it 

 and went into the thicket nearby to the spot where in August 

 I had taken Palcsmnema, the new genus, etc. A small clear- 

 ing had been made here since then and a miscellaneous lot 



