30 PKOCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



This species lias been most frequently encountered on the marine 

 beach from Massachusetts to Louisiana. That it also has a limited 

 distribution inland is indicated by the recovery of specimens at 

 Agricultural and Mechanical College, Mississippi, College Station, 

 Texas, and from Indiana and Idaho. In flight, the adults barely 

 clear the sand over wliich they glide in a swift zigzag course, so closely 

 resembhng that of smaU burrowing Hymenoptera of the beaches that 

 they can be distinguished with certainty only when they alight, as 

 they do at frequent intervals on the surface of the sand. Large num- 

 bers of adults, both males and females, were observed on the blossoms 

 of a common Hydrocotyle of the upper beach, in full bloom along the 

 Gulf coast in early September. The host relationships are not known. 



SENOTAINIA NANA Coquillett 



Senotainia nana Coquillett, U. S. Bur. Ent., Tech. Ser., No. 7, p. 80, 1897. 



Type from Las Cruces, N. M. 

 Microsenotainia nana Townsend, Proc. U. S. Nat. Mus., vol. 49, p. 618, 1915. 



This species is very evidently not the same as Miltogramma iiana 

 Van der Wulp. The latter name has priority, but unless the type 

 which has been lost is located and after reexamination is definitely 

 assigned to this genus, it is deemed inadvisable to propose a new 

 name for Coquillett's species. Townsend proposed a new genus to 

 receive this species on characters which in my opinion are of less 

 than generic rank. 



Male. — Front at narrowest 0.29 of head width (measurements of 

 three as follows: 0.27, 0.30, 0.30); inner orbits diverge from base of 

 antennae, slightly towards vertex, moderately towards bucca; front 

 and face merging from black at the vertex to silvery pollinose at 

 bucca; frontal vitta yellow, linear, scarcely wider than lowest 

 ocellus, obliterated at ocellar triangle; about seven very weak 

 bristles in each frontal row, the rows separated by a distance equal 

 to half width of parafrontal; parafrontals strongly flattened towards 

 vertex, lacking bristly hairs; one reclinate and two proclinate orbital 

 bristles; vibrissae strongly approximated, inserted length of second 

 antennal joint above oral margin; facial ridges bare; antennae 

 extending three-fourths distance to vibrissae, red, the third joint 

 scarcely twice as long as second; arista thickened on basal two- 

 fifths, penultimate joint very short; in profile, axis at vibrissae 

 slightly less than at base of antennae, width of bucca less than that 

 of parafacials and equal to one-sixth of eye height; front projects 

 nearly one-half the eye diameter; parafacials bare, palpi yellow. 

 Thorax, including the scutellum, thinly gray pollinose over black, 

 without spots or distinct vittae; usually one and sometimes two 

 postsutural dorsocentral bristles differentiated; one sternopleural ; 

 three pairs of marginal scutellar bristles. Abdomen red, excepting 



