46 On the Bees of the Family NomadidGe. 



Ericrocis, Cresson, 1887. 



We Iiavc examined Ericrocis lata, Cresson. Its evident 

 affinity is witli Centris, to which it is allied by the short 

 paraglossse and the vary peculiar form of the labial })alpi and 

 galea. The similarity of the galea even extends to the trans- 

 verse brown spots^ though the maxillary palpi in Ericrocis 

 are reduced to two joints. Both Centris and Ericrocis arc no 

 doubt derived from Exomalopsis or a similar form. 



TiiALESTRiA, Smith, 1854. 



We have studied Thalestria smaragdina, Sm., collected by 

 Mr. II. II. Smith at Chapada, Brazil. The maxillary palpi 

 are reduced to two joints. The galea is large and broad, with 

 the series of bristles having tubular sockets, as seen in Xeno- 

 fflossa, while the ill- defined hyaline area is narrowed, though 

 not strongly. The labial palpi are extremely hairy on the 

 inner side, and the third joint is placed at the lateral apex of 

 the second. All this indicates the origin of Thalestria from 

 the Anthophorine series, near to the place of origin of 

 Melecta. 



Thus the " Nomadidse" are of composite origin and should 

 be divided into groups, somewhat as follows : — 



NomadinjB, for Nomada and its allies, to follow the Panur- 



gin?e. 

 Philereminte, for Phileremus and Epeolus. 

 Melectinse, for Melecta, Thalestria, &c., to follow the groups 



of Xenoglossa &c. 

 Ericrocinoe, for Ericrocis, to follow the group of Centris &c. 



The genus Bomhomelecta falls in Melectinaj, and its affinity 

 with Xenoglossa is further indicated by the very long para- 

 glossffi, which, however, are devoid of hairs. The tip of the 

 galea exhibits a number of flattened hairs, and exactly the 

 same, but not so large, are found in Melissodes. The Bomho- 

 melecta studied is B. thoracica, var. fulvida, Cresson. 



It is worth while to remark that the nest-building bees can 

 be recognized by the comb of bristles on the basal part (stipes) 

 of the maxilla. In the parasitic genera this is wholly wanting, 

 the corresponding place presenting at most a series of fine 

 short hairs. 



All the slides used in this investigation were prepared by 

 Mrs. AV. P. Cockerell. 



Eaat Las Veo-as, New Mexico, U.S.A., 

 May 21, 1U02. 



