58 Journal New York Entomological Society. [Voi. ix. 



she digs down vertically and runs the vertical up to the surface. But the 

 opening to this vertical she keeps carefully closed so that not a sign of 

 it appears to casual view. Furthermore, in almost every case the per- 

 pendicular comes up under some bit of natural protection — lichen, 

 moss, grass tuft or anything else in fact. The object of the hovering 

 search by the bees is now apparent ; they are seeking some place that 

 affords a natural protection to the real entrance to the nest and the 

 surface mound does not indicate this entrance within four inches in 

 any direction. Plate IV, Fig. 19, shows a diagrammatic section of 

 the entrance to the burrow. It is obvious that the perpendicular 

 might be fully eight inches from its present location by removal to the 

 exactly opposite side of the mound ; therefore the surface mound does 

 not indicate within 6 or 8 inches the real entrance to the burrow. 

 At first the casts were made through the oblique entrance ; but when 

 it was found that the habit was uniform and that obstructions in the 

 oblique arm often interfered with casting, it was decided to hunt up 

 the perpendicular and cast into that. This was not so difficult after a 

 time, for as soon as a little careful dissecting with the palette knife 

 showed the direction of the perpendicular, one could be sure of find- 

 ing it under the nearest natural shelter. There was always a plug 

 closing this opening except when the bee was out seeking stock for its 

 cells. Therefore it became easy in time to ascertain whether the 

 owner was or was not at home. If we found everything tightly 

 closed, we could take it for granted that the bee was at home ; but 

 was not at all disposed so receive company. Frequently we dropped 

 a little pebble or a pinch of surface sand into the opening and awaited 

 events. In a very few moments the owner appeared at the surface, 

 rarely bringing out more than half her body, looked wildly around in 

 every direction, tried the edges of the burrow with her antennae and 

 then disappeared from view — only for a few seconds however. In an 

 incredibly short time she re-appeared bearing a load of clay which she 

 slapped into place at one edge and dived down for more. In two or 

 three loads she had enough to completely shut the door. At first the dis- 

 colored fresh clay was rather prominent ; but in a short time the sun or 

 drying wind had lessened the contrast so that it did not attract attention. 

 Sometimes we found the door open, but not widely. That is, 

 though the gallery was fully one-fourth inch in diameter, the opening 

 through which the bee came out was not much if any more than half 

 that, just large enough for the insect to get in and out. 



