158 AMERICAN HYMENOPTERA. 



outer iiiai'ffiii broadly iridescent, a green l)and between two pink ones on both 

 wings; apex of front wings sliining. a little violaceous in some lights; nervures 

 black, marginal cell shorter than usual. Legs with pale grayish ochraceous pu- 

 bescence: anterior femora almost naked, but with a spreading tuft of very long 

 whitish hairs near base beneath ; basal joints of tarsi with shining orange rufous 

 hairs on iner side ; brush of hind tarsi rufous. Abdomen short and stout; base 

 of first segment with a thin band of erect pale hairs, no distinct bauds, but second 

 segment, to a large extent, and third and fourth segments entirely covered with 

 short fulvous pile, fifth segment covered with pale ochraceous hairs; the extreme 

 hind margin of the second segment has a very narrow baud of fulvous pile, which 

 is noticeable, through the segment itself not being covered like the following 

 two ; there is a white substance, which I do not understand, in the suture between 

 the second and third segments. 



Var. velutinellus % . — The abdominal pile yellowish white. This looks like 

 a distinct species, but it flies with the normal % , and may be regarded as a di- 

 morphic form of it. 



Hab. — San Rafael, Vera Cruz, March 14, % . Paso de Telaya, 

 April 7, 9 • All were on flowers of plant No. 9, which Dr. Rose 

 recognises as a species of Sida. Collected by Prof. C. H. T. Townsend. 



(23.) JVIegachile sidalcese n. sp. % . — Length nearly 15 mm., anterior 

 wing 11 mm. Black wirh white pubescence, that on the face dense and cream 

 color. Head fairly broad, pubescence of face not mixed with black, arranged as 

 in M. Candida Sm. ; vertex closely punctured, with sparse white pubescence, only 

 noticeable when the insect is held sideways ; cheeks with white hairs, contrasting 

 with the yellowish tint of those on the face; flagelluin dark rufous beneath, last 

 joint not enlarged ; first joint of flagellum about as long as the second ; mandi- 

 bles rufopiceous toward tips, with a brush of cream-colored hairs on upper outer 

 margin ; strongly tridentate, the lower tooth shorter and so placed that it might 

 be described as on the lower margin : the upper two consisting really of a single 

 broad blade deeply notched at the end ; tongue rufous, with its end beset with 

 pale rufous hairs. Thorax dullish, closely punctured, all the pubescence rather 

 dull white, inconspicuous, except a narrow band between mesothorax and scutel- 

 lum, a small patch behind tegulse, a patch below tegulse, hind margin of protho- 

 rax very narrowly, two very narrow lines running thence onto mesothorax, and 

 thin long pubescence on prothorax, pleura, metathorax and more or less on scu- 

 tellum; tegulse punctured, piceous, with ru fotestaceous margins. Wings smoky 

 hyaline, outer margin broadly darker; a narrow dark streak running along costal 

 margin in marginal cell, and a small dark cloud just beyond marginal cell ; ner- 

 vures piceous, marginal cell quite long. Legs with thin, but long white pubes- 

 cence, black with the tarsi cream color ; spines of anterior coxje long and flattened, 

 a little curved, blade like ; femora stout, anterior femora very peculiar ; the upper 

 basal half, which rubs against the thorax, is shining pale yellowish with a rufous 

 tinge ; the lower apical half, which touches the tibia when the leg is flexed, is 

 cream color, meeting the outer side at an acute angle, the margin smooth and 

 appearing as a conspicuous cream-colored line on the flexed leg; anterior and 

 middle tibise more or less cream colored at apes, the apical corners more or less 

 produced into teeth or short spines; anterior tarsi broadened and flattened, first 

 joint hollowed within, somewhat produced at apex, but with no free pr(jjection ; 



