NATURAL GROUPING OF BREMID.-E. 



405 



the surface of the ground, and that as far as known they do 

 not occur in South America. 



However, it may be necessary to use the terms Phanero- and 

 Cryptoschadonenta only provisionally, since Sladen ('12, pp. 36-37 

 and 185) states that Bremus latreillellits, a pocket-maker (Marsi- 

 pcea), also leaves its larvae uncovered. This seems strange, since 

 the other Marsipcea studied are very solicitous to keep their 

 larvae completely covered with wax (cf. Fig. 6), and this fact 



Fig. 6 



FIG. 6. Comb of Bremus americanorum showing (a) three pockets, and (b) 

 worker larvae completely enclosed by wax. Natural size. 



suggests the possibility that Sladen's ('12) observations on Bremus 

 latreillellus may have been made during extremely hot weather, 

 when, due to the softening of the wax, all bumblebee larvae are 

 likely to become exposed. Should subsequent observations con- 

 firm Sladen's ('12, pp. 37 and 185) statement concerning Bremus 

 latreillellus, other terms will have to be substituted for Phanero- 

 and Cryptoschadonenta to bring out the distinctness of this group 

 of bumblebees. 



The various American and European species of bumblebees 

 whose methods of rearing their young have been studied up to 



