JUAN VINAS—THE REVENTAZON FALLEY 225 



and exposing the spider which happened to be turned upside 

 down. The wasp discovered it as it struggled to turn over 

 and after some cautious feeling about managed to plant 

 its sting into the spider's ventral surface, almost between 

 the bases of the legs. This disabled the spider and the wasp 

 then stung it repeatedly over almost its entire body. Twice 

 it left the spider and rested on a nearby stone, then returned 

 to sting it again and again. At last the spider was limp 

 enough and the wasp gathered it up between her legs, turn- 

 ing the bulky victim over and over, and then tried to fly off 

 with it. The spider was too heavy to be easily lifted and 

 as the wasp struggled a train of packmules came along 

 obliging us to move; this frightened the wasp away. 



On the under side of a large rock overhanging the side of 

 the road was a hymenopterous nest covered with a gray 

 papery substance closely resembling the rock in color. This 

 cover was flattened, the nest occupying a concavity in the 

 rock. One July day we stopped to examine it. Cautious 

 lifting of one edge revealed a little stalked comb of several 

 (6-12) cells within and some yellow wasps {Chartergus 

 smithii) who came out to see what the fuss was about. They 

 were little more than one-quarter inch long and had but a 

 short petiole or waist; they belonged to the social wasps 

 (Vespidae). They were very polite, giving us no trouble 

 when we lifted the floor of their house. 



A nest of a different kind was found in April, consisting of 

 mud built around a root exposed by the washing away of 

 the roadside. It was pear-shaped, two and three-quarters 

 inches long and two inches wide at most. In the mud, at 

 unequal distances, were thirty-one cells, some empty, others 

 capped with a cement of different color from the mud. We 

 cut the root across above the nest and brought the latter 

 away with us. On May 16 we found a live black and red 

 wasp half an inch long in our stateroom on the "Prinz Joa- 



