See Fig. 26, p. [71].

[17]

Bull. Mus. Paris, i. 1895, p. 38.

[18]

C.R. Ac. Paris, lxxxvii. 1878, pp. 378 and 535.

[19]

Catalogus Hymenopterorum, Leipzig, 10 vols. 1892-96; Bees, vol. x.

[20]

Zool. Jahrb. Syst. iv. 1891, p. 779. This paper is a most valuable summary of what is known as to the habits of European solitary bees, but is less satisfactory from a systematic point of view.

[21]