DIPTERA. 



348 



the third for only a moderate distance ; third joint large, almost square, the arista inserted at the upper 

 apical corner, the latter about the length of the antenna, stout, blunt at the tip. Cilia of the inferior orbit 

 whitish ; the fine hairs of the lower part of the eyes strikingly long. Prom the mouth there extend several 

 minute slender filaments of peculiar appearance, but I am unable to see what they represent. Thorax 

 and abdomen greenish-black, the small hairs of the latter mostly brownish-black ; bristles of the thorax 

 strong, the acrostichal bristles in two rows. Tegulae yellow, with black cilia ; halteres brownish-yellow. 

 Abdomen with six visible segments ; hypopygium embedded, only the tips of some blackish organs visible. 

 Legs, including the tarsi, uniformly brownish-black, the knees narrowly yellowish ; fore coxae with a 

 greenish reflection ; hind metatarsi shortened (otherwise the tarsi present no tangible peculiarities). 

 Wings as shown in the figure (tig. 18): wide at the tip, with the second and third veins very divergent, 

 and the third and fourth slightly so ; pale yellowish in colour. 



$ . Pace with a distinct suture below the middle, but not projecting in a roof-like manner ; colour as in the 

 male ; palpi and proboscis of usual form, dark brown. Thorax scarcely shining, with olivaceous dust. 

 "Wings lacking the peculiarities of the male. 



Length 3 millim. 



Hab. Mexico, Mexico city {II. H. Smith). 

 Two males, two females. 



PARASYNTORMON. 



Parasyntormon, Wheeler, Proc. Calif. Acad. Sci. (3) ii. p. 41 (1899). 



1. Parasyntormon wheeleri, sp. n. (Tab. VI. fig. 19, antenna from inner 

 side, 8 .) 



8 . Pace long, narrow, a little wider above, black, covered with brown dust, which is somewhat paler below ; 

 palpi and proboscis brown. Antenna wholly black, at least twice the length of the head ; first joint 

 bare; second joint prolonged on the inside of the third nearly to its middle; third joint very long, 

 somewhat oblong, with the upper apical angle drawn out into a slender point a little longer than the 

 main part of the organ, the whole joint hairy ; arista apical, about one-fifth as long as the joint. Front 

 greenish-black, not very shining. Cilia of inferior orbit pale. Thorax dark green above, with an 

 indistinct trace of a coppery line in the middle, and one along the inner dorsal bristles on each side ; 

 acrostichal bristles large, in a single row ; scutellum with a single large pair of bristles ; pleura; dark 

 green, with grey dust. Tegubje yellow, with black cilia; halteres yellow. Abdomen dull bronze-green, 

 the second and third segments with an indistinct antero-lateral yellow spot on each side; venter 

 narrowly yellow. Hypopygium standing out prominently behind the sixth segment, blackish-bronze in 

 colour, rounded ; there are two pairs of very small organs protruding forward, the hinder ones yellowish, 

 rather filiform, with minute hairs, the others brownish, bare, expanded and truncate at the tip. Legs 

 yellow,' all the coxa3 infuscated on the basal two-thirds, the hind femora iu somo specimens slightly 

 infuscated above on the apical half. Pore tarsus of very distinctive form : first joint of moderate length, 

 slightly enlarged at the tip, bearing on the underside near the base a row of four black bristles of 

 increasing length ; second joint one-half the length of the first, swollen on the underside : third joint a 

 little shorter, with a curved bristle on the underside at the base ; the remaining joints of ordinary 

 structure. All the coxa? with coarse black bristles at the tip. Wings subhyaline ; third and fourth veins 

 exactly parallel, the latter ending in the tip of the wing. 



$ . Antennae with the third joint comparatively short, the arista long, bent down near its point of origin ; 

 second joint extending very perceptibly over the third on the inner side. 



Length 2-2 millim. 



Hab. Mexico, Mexico city {II. II. Smith). 



Four males and two females. Named in honour of Professor Win. M. Wheeler, who 

 has worked out this group in the United States. 



