30 PROCEEDINGS OF THE NATIONAL MUSEUM vol.79 



outer ones interrupted at suture and the median one sometimes obso- 

 lete in front; scutellum red except on narrow base; sprinkled with 

 bluish-white pollen, usually bearing three lateral bristles but some- 

 times with four besides the apical pair; calypters opaque, white 

 tinged with yellow. 



Abdomen subshining, usually broadly reddish on sides and apex;: 

 intermediate segments with rather thin gray pollen extending nearly^ 

 to hind margins, the pollen on basal half of fourth interrupted by 

 four blackish longitudinal stripes, which change from light to dark 

 as the angle varies; a narrow dark median stripe visible in most 

 views; basal segments invariably without any median marginal 

 bristles; third with a marginal row of about 10 stout; fourth bear- 

 ing several irregular rows of smaller bristles near the apex and 

 entirely covered with erect hairs in front; the hairs on intermediate 

 segments fine, short, and depressed; venter without defined patches 

 of dense hairs. 



Legs black; front claws and pulvilli equal the length of last two 

 tarsal joints; mid tibiae with one large and usually one or two. 

 smaller bristles on outer front side near middle; hind tibiae thickly 

 ciliate. 



Wings subhyaline, the anterior portion often brownish; venation 

 as usual; third vein with one or two hairs at base; costal spine 

 vestigial. 



Female. — Front 0.294 of the head width (average of five: 0.29; 

 0.30; 0.32; 0.28; 0.28); parafrontals yellow pollinose to vertex and 

 sparsely haired outside of frontal rows; median stripe occupying 

 about one-third the frontal width ; two pairs of verticals and orbitals 

 present ; third antennal joint broader, thorax more densely pollinose 

 and the abdominal hairs coarser than in male; second segment of 

 abdomen with a stout pair of median marginals; hind tibiae with one 

 or more longer bristles in the row on outer posterior edge ; claws and 

 pulvilli short. 



Length, 9 to 13 mm. 



Redescribed from numerous specimens of both sexes from New 

 England, Ohio, Michigan, and Illinois. Two males from Trinidad, 

 West Indies, and 6 from Sanchez, Chihuahua, Mexico, are apparently 

 the same. Two specimens of the original type series were reared 

 from Datana sp. 



The species, as may be noted in the description, is variable, but I 

 have been unable to find any constant characters to separate addi- 

 tional forms. The United States National Museum contains a series 

 reared from one parent host that varies with respect to the number 

 of bristles on the front side of the middle tibiae; while other occa- 

 sional specimens with three sternopleurals or four lateral scutellar 



