110 ' Annals Entomological Society of America [Vol. XII, 



Erax bicolor Bellardi. 



Total length 21 to 26 millimeters; vestiture of the head largely- 

 yellowish white, some black bristles in the mystax; bristles of the palpi 

 almost wholly black. Whole body nearly uniformly gray pollinose, 

 mid-dorsal stripe of the thorax quite plainly black and divided length- 

 wise by a gray interval. In some specimens rather obscure darker 

 spots ' on some of the abdominal segments. Wings hyaline costal 

 border dilated, furcation of the third vein plainly beyond the base of 

 the second posterior cell, basal three-fourths or more of the tibias pale 

 yellowish, otherwise legs black with black bristles. Sixth and seventh 

 abdominal segments silvery, hypopygium large and black. See Figure 9. 



Female colored like the male, except abdominal segments six and 

 seven are velvety black. Oviduct black, about as long as segments 

 four to seven. 



Habitat: Mexico, Texas, Mississippi, New Mexico and 

 Arizona. Twenty-four specimens. 



Bellardi described the species from a female and mentioned 

 the black sixth and seventh abdominal segments which seems to 

 be a peculiarity of this species. It is more evident in some 

 specimens than others. 



Erax willistoni n. sp. 



Male. Total length 22 millimeters. Very dark colored species; 

 mystax black with a few pale hairs intermixed, beard white, palpi 

 with black bristly hairs. Thorax thinly gray pollinose, mid-dorsal 

 stripe and irregular spots on either side black, with black hair and 

 bristles, scutellum gray pollinose with pale hairs on the disc and about 

 eight black bristles on the margin. Wings nearly hyaline, very sHghtly 

 tinged with brown on apical half; costa somewhat dilated, branching 

 of the third vein beyond the base of the second posterior cell, stump 

 very short. Legs with black bristles and pale hairs, extreme apexes 

 of femora, tibiae and tarsi entirely dark reddish brown, remainder of 

 femora black. Abdominal segments two, three and four black above, 

 narrow posterior margin and sides gray pollinose, segments five, six 

 and seven silvery, hypopygium elongate, emarginate at apex, black 

 with black vestiture. See Figure 7. 



Female. Total length 23 millimeters. Colored like the male with 

 segments five, six and seven like those that precede them, ovipositor 

 black, as long as the last four abdominal segments. 



Type male and allotype, on the same pin, collected at 

 Williams, Arizona, July 21, by H. Barber. Deposited in the 

 U. S. National Museum. Five other specimens from Colorado, 

 Arizona and Chihuahua, Mexico, by Tucker, Barber and 

 Townsend. 



