FAM. EMPIDID/E 35 
35. E. labascensis, Wheeler & Melander, Biol. Centr.-ÀAmer. Dipt. Vol. r, Mexico, 
p- 372 [1901] (Hiybos triplex, var. tabascensis). 
36. E. thrixolhrix, nov. sp. Costa Rica. 
37. E. triplex, Walker, List Dipt. Brit. Mus. Vol. 3, p. 486 [1849] (Hy£os); North, Central and South 
Osten-Sacken, Cat. Dipt. N.-Amer. p. 99 and 240 [1878] (Hytos); America. 
Coquillett, Proc. U. S. Nat. Mus. Vol. 18, p. 437 (1896); ibidem, 
Vol. 22, p. 251 (1900); Wheeler & Melander, Biol. Centr.-Amer. 
Dipt. Vol. r, p. 373 [1901] (H£os); Melander, Trans. Amer. Ent. 
Soc. Vol. 28, p. 248, f. 79, 81 [1902] (Hy£os) ; Coquillett, Proc. Ent. 
Soc. Wash. Vol. 5. p. 264 (1903); Bezzi, Nova Acta Akad. Naturf. 
Halle, Vol. 91, p. 3og [19099] (Hytos). 
38. E. verrucicrus, nov. sp. Costa Rica. 
39. E. yucatanus, Wheeler & Melander, Biol. Centr.-Amer. Dipt. Vol. r, Mexico. 
p. 372 [1901] (Hybos triblex, var. yucatanus). 
5. GENUS LACTISTOMYIA, MELANDER 
Lactistomyia, Melander, Trans. Amer. Ent. Soc. Vol. 28, p. 250 (1902); Coquillett, Proc. Ent. Soc. 
Wash. Vol. 5, p. 251 (1903); Bezzi, Nova Acta Akad. Naturf. Halle, Vol. 91. p. 3ot, 311 (1909); 
Coquillett, Proc. U. S. Nat. Mus. Vol. 37, p. 557 (1910). 
Characters. — Robust, thorax and abdomen typically densely covered with fine reddish brown 
tomentum. Head more or less hemispherical, the eyes (C') narrowly separated below the antennz, the 
upper facets larger than the lower; antennz short, the outer joint elongate oval, with a long slender 
terminal arista; proboscis slender, horizontally porrect,-a little shorter than the head; palpi slender, 
porrect also; occipital bristles minute. "Thorax globose, very prominent, no bristles but with short 
scattered fine reddish pubescence, longer at the sides and posteriorly and almost bristle-like at the 
margin of the scutellum. Abdomen stout, cylindrical, deflexed posteriorly; pygidium large, flexed to 
the right, consisting of large convex apically deformed dorsal and ventral valves and a short thin 
compressed hastate terminal filament ; ovipositor elongate and narrow. Legs short, the hind femora and 
tibie remarkably enlarged, the hind femora strongly tuberculate and spiny beneath, their tibi&» bare, 
geniculate at the patella, curved, sharp on the inner edge and with flat sides, hind metatarsi longer than 
the remainder of the tarsus. Wings rather narrowed apically, veins strong, no evident stigma, third 
and fourth veins converging, the first posterior cell much narrower in the margin than at the posterior 
crossvein, discal cell long and narrow. 
Genotype : L. insolita Melander (Pl. b, Fig. 44), the original species. "The genus is restricted 
to tropical America, with one new species from the Philippines. Coquillett, who had not seen spe- 
cimens, concluded that Lactistomyia was synonymous with Zybes, but the genus is more related to 
Euhybos, as shown by the femoral armature and narrowed apical cell. The relation of Hybos, Euhybos 
and Lactistomyia to each other is closely paralleled by the groups of Synueches — i. e. Syneches, Epiceia and 
Harpamerus, and shows the trend of specialization in the Hybotinz. There is a tendency toward the 
closure of the first posterior cell, similar to that which is carried to a greater extent in the Syrphidae 
or Tachinidze, and a corresponding tendency to an elaborate development of the hind legs. 
Geographical distribution. 
1. L. dimidiata, Bellardi (not Walker or Loew), Ditt. Messic. Pt. 2, p. 97 Mexico. 
[1861] (Hybos); Mem. Accad. Sc. Torino (2), Vol. 21, p. 197 [1865] 
(Hiybos). 
sequens, Melander, Trans. Amer. Ent. Soc. Vol. 28, p. 249 [1902] (Hybos) ; 
Bezzi, Nova Acta Akad, Naturf. Halle, Vol. 91, p. 305 [1909] (Hos). 
