Sept., 1916.] ACKERMAN : CaRPENTER-BeES OF U. S. • 197 



Soc. and the Proc. Ent. Soc. of Philadelphia; Smith, Monograph of 

 the Genus Xylocopa, Trans. Ent. Soc. London, 1874; Taschenberg, 

 Zeitschrift fiir den Gesammten Naturwissenschaften, 1879; Perez, 

 Contribution a L'Etude Des Xylocopes, Act. Soc. Bordeaux, LVI, 

 1901 ; and Maidl, Die Xylocopen des Wiener Hofmuseums, 1912, An- 

 nalen Naturhistorischen Hofmuseums. 



For the loan of material through Dr. H. T. Fernald, for the privi- 

 lege of study at the several museums named, and for counsel and sug- 

 gestions given at various times, the writer wishes to express his grati- 

 tude and appreciation to Dr. H. Skinner and E. T. Cresson, Jr., of 

 the American Entomological Society at Philadelphia, to Mr. J. C. 

 Crawford, of the U. S. National Museum, to Mr. Samuel Henshaw, 

 of the Museum of Comparative Zoology at Harvard University, to 

 Mr. Charles Schaeffer, of the Brooklyn Museum, to Mr. George P. 

 Engelhardt, of the Children's Museum of Brooklyn, and to Dr. Henry 

 Franklin, of Amherst, Massachusetts. 



At this point I desire to express my sincere thanks to Dr. H. T. 

 Fernald for his friendly guidance and encouragement and for his 

 many helpful suggestions in this work. To Dr. G. C. Crampton I 

 also wish to acknowledge my appreciation of his willing aid at all 

 times. 



History. 



The earlier writers included species of Xylocopa under various 

 genera. Linne, Fabricius and others described many species which 

 belong to Xylocopa under the genus Apis. Fabricius, Illiger and 

 Lepeletier placed some species under Bonibiis; Jurine under Brcniis 

 and Trachnsa; Westwood under Centris; Lepeletier under Lestis; 

 and Klug under Mcgilla. 



The genus Xylocopa was established by Latreille in 1802 and he 

 included under it three species, Apis violacca Fabr. ; morio Fabr. ; 

 and hrasiUanoriun Fabr. Which one of these three species was the 

 type of the genus he failed to designate. 



In 1838 Westwood proposed as a connecting link between Antho- 

 phora and Xylocopa a new genus, Mesotrichia, which resembled 

 Xylocopa because of its habitat and AiitJwpIiora because of its extra- 

 ordinary formation of the intermediate legs, and describes one spe- 

 cies, M. torrida. Again in 1840 Westwood split Xylocopa, forming 



