196 Journal New York Entomological Society, t^'o'- >^-'^tv, 



halteres yellowish transparent basally, yellowish brown apically. Legs mostly 

 yellowish gray and sparsely clothed with moderately long, whitish hairs; distal 

 tarsal segments somewhat darker ; claws moderately stout, evenly curved, 

 finely denticulate and with a minute tooth subapically, the pulvilli a little 

 shorter than the claws. Genitalia; basal clasp segment very short, broad; 

 terminal clasp segment moderately long, narrowly oval; harpes extended, 

 foliate, the basal angles produced laterally as chitinous, tooth-like processes, 

 obliquely truncate ; distal angles with the margin strongly chitinized and bear- 

 ing three or four short, stout teeth. Type Cecid. 1649. 



THE CARPENTER-BEES OF THE UNITED STATES 

 OF THE GENUS XYLOCOPA.^ 



By Arthur J. Ackerman, 

 Amherst, Massachusetts. 



Introduction. 



This paper forms the major part of a thesis for the degree of 

 master of science at the Massachusetts Agricttltural College, and it 

 has been prepared under the supervision of Dr. H. T. Fernald. It 

 is an endeavor to make more easy the identification of the bees of 

 this genus. 



The collections upon which the work in this paper is based are 

 those of the American Entomological Society in Philadelphia, the 

 United States National Museum, the Museum of Comparative Zool- 

 ogy of Harvard University, the Brooklyn Museum, the Children's 

 Museum of Brooklyn, the collection of the Massachusetts Agricul- 

 tural College, the private collection of Dr. G. C. Crampton, and other 

 smaller collections. The few types existing in this country have been 

 examined and descriptions made from them, added to by the exami- 

 nation of a large series of specimens; redescriptions of all the species 

 and a key for their separation are also included. 



Earlier works and literature found to be 'of great value in the 

 preparation of this paper are: Illiger, Magaz. f. Insectenk., 1806; 

 Lepeletier, Hist. Nat. Insect. Hymen., II, 1841 ; Smith, Cat. Hymen. 

 Brit. Mus., II, 1854; Cresson's descriptions in the Trans. Amer. Ent. 



1 Contribution from the Entomological Laboratory, Massachusetts Agri- 

 cultural College. 



