136 GENERA OF HYMENOPTERA. 



genera, together with Emphor, Enteehnia, Habropoda, Anthophora 

 and Clisodon, have been made the subject of an interesting paper by 

 Mr. Patton, entitled, " Generic Arrangement of the Bees allied to 

 Mel'imodes and Anthophora (Bull. v. U. 8. Geo. Surv. 1879)," in which 

 the characters are given at length. 



The genus Xylocopa, commonly known as "Carpenter Bees," from 

 their habit of boring tunnels in posts, rails, etc., in which to nidificate, 

 contain some of the largest species of the family. 



The genera Bombus and Apis are too well known to need any ref- 

 erence here to their structural characters. They differ from all other 

 bees in their social habits, being composed of males, females and 

 workers. The species of Bomhus, or " humble-bees" construct their 

 nests generally under ground in meadows, pastures, etc., and form 

 societies of more or less extent ; their union, however, lasts only until 

 the cold weather destroys all but a few impregnated females, who 

 survive to found fresh colonies the following spring. 



Apathm is a parasitic genus of bees which inhabit the nests of the 

 Bombi. " What office," says Smith, " these bees perform in the 

 economy of the nest has not been discovered ; they live on the most 

 friendly terms with the industrious part of the community, and it is 

 probable that upon them devolves some important office, the nature 

 of which it would be very interesting to discover." The genus dif- 

 fers from Bombiis principally in the absence of the corbicula on the 

 posterior legs of the 9 » the tibia? in both sexes being outwardly con- 

 vex and denselv clothed with short hairs. 



The genus Apis contains the common "Hive-Bee," mellifica, which 

 is cosiiV politan, lud upon which volumes have been written, yet 

 many intere-/ing ^l ints in their economy still remain undetermined. 

 " We can scarcely estimate," says Smith " the value the products of 

 the hive must hare been to man in ancient times ; but when we re- 

 member that honey must have formed the staple commodity which 

 our forefathers applied to all the uses for which sugar is now sub- 

 stituted, and at the same time recollect even the present value of the 

 wax, we shall arrive at a considerable estimate of the benefits de- 

 rived from the^e industrious insects." 



