168 HYMENOPTERA. 



banks near the walk. The holes were four to six inches deep. 

 In beginning its hole the wasp dragged away with its teeth a 

 stone one half as large as itself to a distance of eight inches 

 from the hole, while it pushed away others with its head. In 

 beginning its burrow it used its large and powerful jaws almost 

 entirely, digging to the depth of an inch in five minutes, com- 

 pleting its hole in about half an hour. After having inserted 

 its head into the hole, where it loosened the earth with its 

 jaws and threw it out of the hole with its jaws and fore 

 legs, it would retreat backwards and push the dirt still 

 farther back from the mouth of the cell with its hind legs. In 

 cases where the farther progress of the work was stopped by a 

 stone too large for the wasp to remove or dig around, it would 

 abandon it and begin a new hole. Just as soon as it reached 

 the required depth the wasp flew a few feet to the adjoining 

 bank and falling upon an Orchelimum vulgare or O. gracile, 

 stung and paralyzed it instantly, bore it to its nest, and was out 

 of sight for a moment, and while in the bottom of its hole 

 must have deposited its egg in its victim. Reappearing it be- 

 gan to draw the sand back into the hole, scratching it in quite 

 briskly by means of its spiny fore tarsi, while standing on its 

 two hind pairs of legs. It thus threw in half an inch of dirt 

 upon the grasshopper and then flew off. In this way one Sphex 

 will make two or three such holes in an afternoon. The walk 

 was hard and composed of a coarse sea-gravel, and the rapidity 

 with which the wasp worked her way in with tooth and nail was 

 marvellous. 



Sphex tibialis St. Fargeau is a black, stout, thick insect. 

 Mr. J. Angus has roared this species, sending me the larvae in 

 a cavity previously tunnelled by Xylocopa Virginica in a 

 pine board. The hole was six inches long, and the oval cylin- 

 drical cocoons were packed loosely, either side by side, where 

 there was room, or one a little in advance of the other. The 

 interstices between them were filled with bits of rope, which 

 had perhaps been bitten up into pieces by the wasp itself ; while 

 the end of the cell was filled for a distance of two inches with a 

 coarse sedge arranged in layers, as if rammed in like gun-wad- 

 ding. The cocoons are eighty to ninety hundredths of an inch 

 long, oval lanceolate, somewhat like those of Pompilus. They 



