HOUGH: SOUTH AMERICAN MUSCID.E. 209 



present. The ciliiT of the posterior orbit and the hair of the 

 occiput are as in the male. Posterior orbit yellow pollinose. 



In both sexes the ground color of the bucca varies from a 

 rather pale yellow through orange, brownish yellow and brown 

 to almost black. It is always covered with yellow pollen, and 

 quite thickly beset with whitish or yellow hairs, which are 

 much longer toward the occiput. Its cephalic border has a 

 row of small bristles. 



The gena has a yellow ground color and is thickly yellow 

 pollinose. It has no bristles. 



The vibrissal ridges have a yellow ground color and thick 

 yellow pollen. The vibrissal angles are somewhat dorsad the 

 mouth edge and distinctly convergent. There are no large 

 bristles except the principal vibrissa, but dorsad this the ridge 

 is rather thickly beset on its lateral surface with exceedingly 

 minute bristles or hairs. 



The antennae are yellow, with the cephalic border and lateral 

 surface brown. The third joint is 1 mm. long, and the sec- 

 ond 0.3 ram. The arista is thickly plumose to its very tip ; its 

 rachis is yellow on its thickened basal half, the rest appear- 

 ing black. 



The palpi are yellow, with black bristles. The halteres are 

 yellow. 



The thorax presents varying shades of metallic blue, green, 

 and purple. The dorsum has three broad but very faint, almost 

 black, stripes, one in the median line and one on each side just 

 laterad the line of the dorso-central bristles. The extreme 

 cephalic end of the thorax is white pollinose, even the humeri 

 presenting this appearance by a sufficiently oblique light. 

 The prostiga is light brown to dark brown ; not at all a promi- 

 nent object. The ch;rtotaxy of the thorax is shown in figure 5. 

 The dorso-centrals have precisely the same arrangement and 

 variations as in C. segmentaria. The squamula thoracalis has 

 its caudal half black, with a light border, and its cephalic 

 half white ; its dorsal surface is hairy, some of the hairs 

 appearing black and some white. • The squamula alaris, 

 with the wings folded, is blackish on its mesal half or more 

 and white on the remainder. On its dorsal surface, at the 

 extreme lateral border, is a tuft of black hairs. The wing 

 is shown in figure 6. It is mostly hyaline, but the base is 



