268 CHARLES W. JOHNSON. 



line? to tlio orbits: vertex, antennie anrl ijroboscis black. Thorax black, with 

 yellow pile, a small spot at the humeri ; posterior angles and a lateral line ex- 

 tending to the base of the suture, yellow ; ])leuriB yellow, with two black spots, 

 the anterior one connected with the black of the pectus; scutellura yellow; 

 spines small, halteres light yellow. Abdomen black, with yellow and black pile ; 

 second segment with a subtriangular marking at the lateral posterior angles: 

 third and fourth with a transverse marking on the lateral posterior margins; 

 that on the fourth about one-half the size of that en the third ; fifth with a lateral 

 and posterior margin ; lateral margin narrowing anteriorly ; vertex yellow. 

 Femora black, distal half of the tibiae brownish black, the anterior and middle 

 tibiae showing on the underside an apical arid medial annuli, tip of the femora 

 and base of the tibise yellow, base of the tarsi red, the remainder a dark brown. 

 Wings hyaline, veins reddish, discal cell emits three veins. 



Cue specimen J Colorado (J. M. Aldrich). 



This species is nearest allied to 0. hierofj/ijphica, l)ut differs in 

 liavinti' a nuich narrower front, a short longitndinal frontal line of" 

 black, the absence of a continuous lateral line on the thorax and 

 narrower alxlonien. The specimen before me is bright yellow, while 

 0. luero(//iij»/iica is bright green, but this is of little moment. 



OUoiitoinyia occipitalis n. sp. (PI. iv, figs. 23, 24). 



Length 'Jj 9 10 mm. % . — Face, frontal and vertical triangle black ; shining, 

 with whitish pile; lower half of the face more or le,ss yellowish. Antennae, first 

 and basal half of the second brown, outer half of the second, and the third black ; 

 ocelli yellow. Thorax black, with yellowish pile ; most prominent on the pleursB ; 

 pleurtB marked irregularly with yellow (in one specimen black), pectus and scu- 

 tellum black ; a narrow apical margin between the spines and the spines yellow ; 

 spine very small. Abdomen black, .segm«ints marked with yellow as follows : 

 second with a wide, lateral margin, sliglitly protracted along the lateral posterior 

 margin ; third and fourth with a narrow lateral margin and a triangle at the 

 posterior angles (in one specimen obsolete on the fourth) ; fifth with a narrow, 

 lateral and posterior margin ; venter yellow ; base of the third, fourth and fifth 

 segments narrowly margined with black; margin interrupted on the third. 

 Legs black, tip of the femora, base of the tibiae and tarsi yellow ; outer half of 

 the tarsi brownish. Wings hyaline, veins dark brown ; discal cell emits three 

 veins, third longitudinal vein simple. 



9. — Face, front and occiput yellow, the latter very prominent: mouth, and 

 on each side, and at the upper angle of the oral margin, black ; a large, black, 

 transverse spot surrounds the base of the antennse. which i)roject above and below 

 the antennae and at tiie lower corners; a transverse black spot extends from the 

 frontal orbits and almost connects with that surrounding the antennae: a large 

 black spot surrounds the ocelli, which is very narrowly attenuated to the vertical 

 orbits ; a narrow line also extends over the vertical angle. Thorax dull black, 

 with very short yellowish pubescence; -posterior angle, from which extends a 

 post-alar line nearly reaching the suture, and the pleurae yellow ; scutellum black, 

 widely margined with yellow. Abdomen dull black; the markings ditt'er from 

 those of the male in being less triangular, and might be described as latera' mar- 



