408 O. E. PLATH. 



SUMMARY. 



1. Contrary to the assertions of Wagner ('06), biological 

 characters are of considerable importance in determining the 

 relationships between the various species of bumblebees, while 

 structural characters frequently make it possible to draw in- 

 ferences as to the habits of these insects. 



2. Our North American Marsipcea at least Brcmus americano- 

 rum and Bremus fervidus feed only their worker brood through 

 pockets, while those larvae which are destined to become queens 

 and males are fed by regurgitation. 



3. The use of the terms Pollen- primers, Carder-bees, and 

 Long-faced humble-bees (cf. Sladen '12) is impracticable in any 

 comprehensive classification of the Bremidae. 



4. Von Buttel-Reepen's ('03) explanation of the pollen-priming 

 habit of bumblebees is not substantiated by the biology of some 

 of our North American species. 



LITERATURE CITED. 

 Ball, F. J. 



'14 Les Bourdons de la Belgique. Ann. Soc. Ent. Belg., Vol. 58, pp. 77-108, 



PI. I. 

 Buttel-Reepen, H. v. 



'03 Die stammesgeschichtliche Entstehung des Bienenstaates, sowie Beitrage 

 zur Lebensvveise der solitaren und sozialen Bienen (Hummeln, Meliponen, 

 etc.). Georg Thieme, Leipzig. 



'07 Zur Psychobiologie der Hummeln. I. Biol. Centralbl., Vol. 27, pp. 579-613. 

 '14 Dysteleologen in der Natur. (Zur Psychobiologie der Hummeln II.). 



Biol. Centralbl., Vol. 34, pp. 664-684. 

 Dalla Torre, K. W. v. 



'82 Bemerkungen zur Gattung Bombus Latr. Ber. naturw.-med. Ver. Inns- 

 bruck, Vol. 12, pp. 14-31. 

 Franklin, H. J. 

 'i2/'i3 The Bombidae of the New World. Trans. Amer. Ent. Soc., Vol. 38, pp. 



177-486, Vol. 39, pp. 73-200, Pis. 1-22. 

 Friese, H. und Wagner, F. v. 



'10 Zoologische Studien an Hummeln. I. Die Hummeln der deutschen Fauna. 



Zool. Jahrb., Abt. Syst., Vol. 29, pp. 1-104, Pis. 1-7. 20 figs, 

 Frison, T. H. 



'17 Notes on Bombidae, and on the Life History of Bombus auricomus Robt. 

 Ann. Ent. Soc. Amer., Vol. 10, pp. 277-286, Pis. 23 and 24. 



'03; Saunders, '09; Sladen, '12; and Frison, '17); however it seems desirable to 

 look for additional biological characters before separating this group from the other 

 Amarsipcea. 



