INHABITANTS OF AN OLD STUMP. 43 



returned, but again we failed to see what she carried. She flew 

 with great rapidity and we scarcely canght sight of her before 

 she vanished into her nest. We could not but wonder at the 

 ease and certainty with which she recognized her own doorway 

 among the hundreds of holes on the side of the stump. Thi& 

 power of localization, while it is one of the most common among 

 wasps, is surely also one of the most remarkable. 



Our little RJiopahim pediccUatwm, for that proved to be her 

 name, made six more journeys within the next two hours. At the 

 end of this time we opened the tunnel, and, after a great deal 

 of sawing and cutting, succeeded in finding the nest five inches 

 from the surface. It was nothing but a slight enlargement of 

 the gallery, in the soft decaying wood. In it we found thirty- 

 three gray gnats of the genus Chiroiiormts, all of them being 

 dead excepting two. On one of the dead ones was the egg, 

 which had probably been laid within a few hours. 



The egg hatched two days later, on July twelfth, but on the 

 fifteenth the larva died. By this time many of the gnats looked 

 very dry, although we had tried to arrange for both moisture 

 £nd ventilation by packing the bottom of the tube w^th pith 

 and covering the top with muslin. 



Further watching gave us one more wasp of this species, in 

 the same stump. This time the nest was only two inches from 

 the surface. It contained four dead gnats and two live ones, 

 but no egg, sho^^^ng that the egg is not always laid on the first 

 ones stored. 



Much later in the season, toward the end of August, we found 

 another species of Rliopalum which proved to be new, and for 

 which Mr. Ashmead has proposed the name ruhrocinctum since 

 it wears a red girdle around the front end of the abdomen, being 

 otherwise dressed in black like pedieillatum. It makes its home 

 in the stalks of raspberry bushes. We opened a stem which 

 contained thirteen compartments, separated by partitions of 

 pith. These were filled, with black, gray, and green gnats, 

 which were packed in so closely that they were doubled over 

 and pressed all out of shape. Each cell contained from twenty- 



