140 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



first segment ; on the third segnieut, on the contrary, it is tapering an- 

 teriorly; fourth segment with a black crossband a little beyond the 

 middle, with a subtriangular expansion in the middle reaching toward 

 tlie tifth segment; fifth segment black on the sides, in the male the hy- 

 ])opygium black ; the abdomen is clothed with short black pile on its 

 black portions and with yellowish i>ile on the yellow regions, especially 

 on the sides of the second segment and on the posterior part Femora 

 black; knees and basal half of the tibi?e brownish-yellow, tarsi black. 

 Wings hyaline ; latter half of the costal cell and the interval between 

 the auxiliary and first longitudinal vein as far as the stigma brownish; 

 stigma dark brown, central cross-veins and small cross-veins with well 

 defined brown clouds ; the second vein ends in the first some little dis- 

 tance before the tip of the latter. 

 Five specimens. 



Volucella isabellina, u. sp. 

 Eahitat. — Arizona ! 



9 . Length, 15 to 16"". Face pale whitish-yellow, with a narrow 

 brown stripe on the lower two-thirds, paler and obsolete above; pile in 

 the middle black, on the sides mixed with white ; cheeks with a rather 

 narrow brownish-black stripe running from the eye to the tip ; behind 

 with a fringe of white pile. Front of the same color as the face with 

 side grooves and clothed with black pile. Front gently and evenly con- 

 vex ; face lightly concave below the antennae, receding on its inferior 

 half. Antennae brownish, or reddish ; rather short, the third joint 

 somewhat longer than in avida, expanded on its basal portion. Thorax 

 greenish-black; on each side between the humerus and scutellum a rather 

 broad dull honey-yellow stripe ; in front of the scutellum a yellowish, 

 rather obscure, parallelogram ; the black is thickly dusted, leaving slen- 

 der stripes and the narrow borders shining blackish ; sides of the dor- 

 sum and the pleurae beset with the yellowish- white pile, on the post-alar 

 callosities mingled with black hair. Scutellum yellowish, subtranslu- 

 ceut, beset with black ])ile on its disk and edge. Abdomen light yel- 

 low ; first segment black, second segment i)osteriorly with a rather nar- 

 row black margin, obsolete in the middle, expanded somewhat toward 

 the sides, in front with a narrow black triangle reaching to about the 

 middle of the segment ; third segment with the anterior margin light 

 yellow, more or less red on the middle part, a deep black on the poste- 

 rior portion, which on the sides reaches to near the middle of the seg- 

 ment ; this black border is a little wider than that on the preceding seg- 

 ment and like that interrupted, or obsolete in the middle; fourth seg- 

 ment with a black spot on each side on it posterior margin ; on the an- 

 terior angles of each segment there is light yellow pile, elsewhere with 

 short black hairs. Femora black at the base, on the other part, and the 

 basal portions of the tibiae and tarsi, brownish-yellow; terminal part 

 of tibiae and the last three joints of all the tarsi, darker, the latter black 



