98 AMERICAN HYMENOPTERA. 



outer sides, of nearly equal width throughout their length, without 

 long hind fringes. 



Dimensions. — Length : queen, about 17 mm. ; worker, about 11 

 mm. ; male, 12 mm. to 13 mm. Spread of wings : male, 26 mm. to 

 28 mm. 



Variation. — The principal variation in this species is in the 

 coloration of the third dorsal abdominal segment. If it 

 seems desirable to give names to distinguish the form in 

 which this segment is entirely yellow from the one in which 

 its extreme sides are dark, possibly the name zueisi must go 

 with the former, while the name viontezumce indicates the 

 latter, variation. Perhaps a new name should be given to 

 the first form. 



Habitat. — Our certain records for this species are : Mexico 

 (Oajaca and Tlalpam) and Costa Rica (San Carlos). 



This species has its nearest relative in B. nigrodorsalis. It 

 may be distinguished from that species by its having the dor- 

 sum of the thorax dark, without the yellow band across the 

 front part and without the yellow fringe on the hind margin 

 of the scutellum. It may be at once separated from pulcher, 

 ephippiatus and wihnattce by the ferruginous hair on the apex 

 of its abdomen and probably also by its somewhat longer 

 malar space. I consider montezumce and nigrodorsalis the 

 most primitive of all the New World species of Bombus. 



Boiubus (Bombus) iiigTOClorsalis Franklin. 

 Bombus nigrodorsalis Franklin, Ent. News, XVIII, 1907, p. 90. 



" " var. laticollis Franklin, Ent. News, 1907, p. 91. 



Types. — Typical nigrodorsalis was originally described from 

 one queen and one worker. These specimens together with 

 five queens and one worker (paratypes) are in the collection 

 of the United States National Museum. I do not now con- 

 sider the form laticollis to be a good subspecies, but rather 

 look upon it as a color variant. The specimen, from which 

 this variant was described, was a queen. It is also in the 

 collection of the United States National Museum. The type 

 of the male, here described for the first time, is in the same 

 collection. All these type specimens were collected by C. 

 H. T. Townsend in Meadow Valley, head of Rio Piedras 



