APIAEI^. 139 



three points. First, the rapidity with which tlie insect worked ; 

 secondly, the tenacity witli which she kept her original position 

 whilst excavating ; and thirdly, her constantly going over 

 work which had apparently been completed. . . . The lid is 

 excavated and rendered concave on its onter or upper surface, 

 and is convex and rough on its inner surface ; and, in fact, is a 

 simple repetition of the first-formed portion of the cell, a part 

 of a hollow sphere." 



The largest species of Osmia known to us is a very dark-blue 

 species which seems to be undescribed. We will call it the 

 wood-boring Osmia {Os^nia lignivora). It is larger than 

 the Osmia lignaria of Say, being just half an inch long. The 

 head is much shorter, and less square than in Say's spe- 

 cies. The front of the head below the antennae is clothed with 

 dark hairs, but above and on the thorax with yellowish ochreous 

 hairs. The body is deep blackish blue, with greenish reflec- 

 tions. We are indebted to a lady for specimens of the bees 

 with their cells, which had been excavated in the interior of a 

 mai^le tree several inches from the bark. The bee had industri- 

 ously tunnelled out this elaborate burrow (Plate 4, Fig. 12), 

 and, in this respect, resembles the habits of the Carpenter-bee 

 (Xylocopa) more closely than any other species of its genus. 



The tunnel was over three inches long, and about three- 

 tenths of an inch wide. It contracted a little in width between 

 the cell, showing that the bee worked intelligently, and wasted 

 no more of her energies than was absolutely necessary. The 

 burrow contained five cells, each half an inch long, being 

 rather short and broad, with the hinder end rounded, while the 

 opposite end, next to the one adjoining, is cut off squarely. 

 The cell is somewhat jug-shaped, owing to a slight constriction 

 just behind the mouth. The material of which the cell is com- 

 posed is stout, silken, parchment-like, and very smooth within. 

 The interstices between the cells are filled with rather coarse 

 chippings made by the bee. 



The bee cut its way out of the cells in March, and lived for 

 a month afterwards on a diet of honey and water. It eagerly 

 lapped up the drops of water supplied by its keeper, to whom 

 it soon grew accustomed, and seemed to recognize. 



The female of Osmia lignaria Say MS., according to Dr. 



