24 DIPTEEA. 



and purple reflections. Thoracic dorsum red, with a very slight coppery reflection ; scu- 

 tellum metallic bronze-green, its hind margin yellow ; metanotum metallic green ; pleurae 

 pale yellow ; a large triangular black spot, with a green metallic reflection, occupies nearly 

 the whole space in front of the mesopleural suture ; sternum, between the front and 

 middle coxae, of the same colour, but bisected by a slender yellow line ; front and 

 middle coxae yellow, with a black spot on the outside (wanting in my female speci- 

 men) ; hind coxse almost entirely black. Front legs pale yellow ; middle legs yellow, but 

 the femora more or less brown on the distal half, the tibiae brownish on the underside, 

 and beset with microscopic black pile, the upperside whitish, glabrous ; the trochanters 

 and the base of the femora of the hind legs are pale yellow, the rest black, with a 

 metallic reflection ; hind tibiae whitish-yellow, brown on the underside of the proximal 

 third, the distal third brown on both sides ; tarsi yellow ; the hind pair has the four last 

 joints dark brown. Halteres yellow at the base, the knob brownish. Abdomen with the 

 first and second segments pale yellow : the first with a metallic blue triangular spot on 

 the lateral margin on each side ; the second with a similar spot, but larger, occupying the 

 whole lateral and a portion of the posterior margin ; segments 3-6 metallic blue, with 

 purplish reflections ; on the third segment the posterior margin has a narrow yellow 

 border, attenuated on each side, and not quite reaching the lateral margin ; a similar 

 yellow border, but still narrower, on the fourth segment ; venter and the three first 

 segments pale yellow, metallic blue on the sides, the other segments metallic blue. 

 Wings subhyaline, with a slight grey tinge; stigma dark brown. A single male 

 specimen from Guatemala ; a female from Brazil in the British Museum collection. 



The not equidistant ocelli and the not contiguous eyes of the male prove this to be 

 a true Sargus ; the abdomen is, however, much broader than in the European species 

 of the group, S. cwprarius, S. infuscatus, &c. The end of the second vein is a little 

 less parallel to the end of the first than in those species. The tibiae of the male show 

 the usual sexual characters. 



PTECTICUS. 



Ptecticus, Loew, Verh. zool.-bot. Ges. Wien, v. p. 142 (1855). {Plectiscus, 1. c. on the plate, 

 is a misprint ; see O. Sack. Catal. Dipt. N. Am. 1878, p. 224, note 53.) 



l. Ptecticus figlinus, sp. n., <j . 



Thorax reddish -brown ; abdomen metallic violet-brown, with yellow cross-bands on the hind margins of the 



segments ; wings with a pale brownish tinge, yellowish between the discal cell and the costa. 

 Length 15 millim. 



Hab. Guatemala, San Geronimo (Champion). 



Face and the vesicular frontal triangle dingy pale yellowish ; front brownish, the ocellar 

 spot darker; antennae reddish-yellow. Thorax reddish-brown, subopaque above, and 

 clothed with a short fulvous, erect pubescence ; pleurae and metanotum more shining and 



