i BEES ARCIIIAPIDES 2 I 



blance \vith the Andrenidae. This arrangement is by no means 

 satisfactory, but as the tropical bees have been but little collected, 

 and are only very imperfectly known, it is clear that we, cannot 

 hope for a better classification till collections have been very 

 much increased and improved. The arrangement adopted in 

 Dalla Torre's recent valuable catalogue of bees 1 recognises no less 

 than fourteen primary divisions, but is far from satisfactory. 



The two genera Prosopis and Sphecodcs have been recently 

 formed into a special family, AKCHIAPIDAE, by Friese, 2 who, how- 

 ever, admits that the association is not a natural one. The 

 term should be limited to Prosopis and the genera into which it 

 has been, or shortly will be, divided. The primitive nature of 

 the members of this genus is exhibited in all the external 

 characters that are most distinctive 

 of bees; the proboscis (Fig. 9, B, C), is 

 quite short, its ligula being very short, 

 and instead of being pointed having 

 a concave front margin. The body 

 is almost bare, though there is some 

 very short feathered plumage. The 

 hind legs are destitute of modifica- 

 tions for industrial purposes. Owing 

 to these peculiarities it was for 

 long assumed that the species of FIG. 10. 

 Prosopis must be parasites. This 

 is, however, known not to be the 



case so far as many of the species are concerned. They form 

 cells lined with a silken membrane in the stems of brambles 

 and other plants that are suitable, or in burrows in the 

 earth, or in the mortar of walls ; individuals of the same species 

 varying much as to the nidus they select. The food they store 

 in these cells is much more liquid than usual, and has been 

 supposed to be entirely honey, since they have no apparatus for 

 carrying pollen. Mr. E. C. L. Perkins has, however, observed 

 that they swallow both pollen and nectar, brushing the first- 

 named substance to the mouth by aid of the front legs. He 



1 Catalogns Hymenoptcrorum, Leipzig, 10 vols. 1892-96 ; Bees, vol. x. 



- 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. 



