June, igoi.] Smith : On Some Digger Bees . 59 



The method of digging is interesting and was studied on a number 

 of examples confined in glass tubes. The fore legs were used to scrape 

 up material which was made into a lump clasped between the abdomen, 

 breast and middle and hind femora. Then the insect crawled up 

 actively but awkwardly, moving middle and hind legs as little as pos- 

 sible and confining the motion to the tibiae and tarsi. Arrived at the 

 surface or dumping ground the load was deposited in place by turning 

 a complete sumersault and then diving down into the burrow head 

 first. When it was a matter of closing the opening, the upper surface 

 of the abdomen was used to press each load into place, but everything 

 was done so rapidly that it all seemed part of one motion. 



The bee is intensely and nervously active at all times when ob- 

 served. It is never quiet a moment, but bustles about as if every 

 second counted for much. Antennae, legs and palpi are always in 

 motion, whether in the burrow or on a flower, gathering pollen. It 

 gives the impression of nervous haste, yet the haste seems well directed 

 and effective, no false moves or motions being apparent. 



The antennae of the female are rather short and a little stouter 

 than those of the male, being represented at Fig. g of Plate III. 

 The scape is about one-half as long as the funicle, or one -third of the 

 entire antenna. Joint 2 is longer and more slender than the two next 

 following, and these — -2, 3 and 4 — are smooth, sparsely punctured and 

 only thinly pubescent. Joints 5-12 are stouter and gradually increase 

 in length, 12 being almost as long as 10 and 11 combined, and longer 

 than any other two joints in the antenna. These joints — 5 to 12 — 

 are densely punctured and pubescent, the surface sensitive and opaque, 

 especially toward tip. 



It has been stated that, after making sure that the oblique entrance 

 was an invariable habit, casts were made directly into the perpendicu- 

 lar because the former was often obstructed. We found this especially 

 in the afternoon and finally concluded that the insect used this gallery 

 as a storehouse for sand mined during the day. It had been noted be- 

 fore this that the sand-heaps were all fresh each morning, new material 

 still damp being found on every active hill. No such fresh material 

 was seen at any time during the day, nor were the bees ever seen forc- 

 ing out sand — everything of that kind was done at night. We con- 

 cluded, therefore, that what the bee brought up during the day, was 

 stored until night and then forced out through the false mouth. At 

 times digging will cease altogether. For instance, on one occasion a 



