1965] 
Fairchild — Neotropical T abanidae 
213 
Hhnantostylus Lutz, as suggested by Stone (1934) and Barretto 
( 1949), is very similar to Lepiselaga but differs structurally in having 
a strong tubercle at vertex with well marked vestiges of ocelli, a 
quite different frontal callus, and in lacking the narrowed discal cell. 
The labella are also without sclerotized strips, and the palpi less 
highly modified. The palpi of male Himantostylus are porrect, oval, 
inflated and shiny, those of Lepiselaga are decumbent and similar 
to the female, though more slender and less flattened. 
Many of the peculiarities and similarities of Lepiselaga and 
Himantostylus may be due to what might be termed mimetic con- 
vergence. All the species bear a strong resemblance in size, coloration, 
and to some extent in actions, to stingless bees of the genus Trigona. 
This resemblance is strongest in Hhnantostylus and the subgenus 
Conoposelaga, less marked in L. crassipes. The latter at least is 
preyed upon by certain solitary wasps, as noted by Bates over a 
century ago (Bequaert 1926). Himantostylus intermedius is espe- 
cially bee-like in its actions. In a jungle camp on the Rio Tacarcuna, 
Darien Province, Panama, I collected a good series of this species, 
and had an opportunity to observe its actions. The flies flew silently 
close to the ground, clustering on my canvas and rubber boots and 
seldom alighting above the ankles. They crawled busily over the 
boots in the manner of stingless bees investigating an attractive sur- 
face, but were unable to penetrate the thick material. When a hand 
was placed on the boots, they crawled over the fingers, but made no 
attempt to bite. L. crassipes also seems to prefer the lower part of 
the body, and also sometimes crawls about in a bee-like manner, but 
it bites viciously when a suitable site is found. Little is recorded 
as to the habits of the other species. Lutz (1913) notes that the 
original series of L. aberrans was taken at 3 p. m. and bit man and 
horses avidly. The original specimens of L. albitarsis were collected 
by D’Orbigny in 1827* His original journal is preserved in the 
Explanation of Plate 15 
Figures of heads, notopleural lobes and wing are to the same scale, The 
wing measures 5.3 mm. Figures of antennae and palpi are also to the same 
scale, but twice the magnification of heads. 
Fig. 1 Himantostylus intermedius Lutz, a, palpus; b, dorsal view of noto- 
pleural lobe ; c, antenna ; d, head, frontal view. Panama. Fig. 2 Lepiselaga 
(Conoposelaga) albitarsis Macq. a, palpus; b, notopleural lobe; c, antenna. 
Argentina. Fig. 3 Lepiselaga (Conoposelaga) aberrans Lutz, a, palpus; b, 
notopleural lobe; c, antenna. Paratype. Fig. 4 Lepiselaga ( Conoposelaga ) 
colombiana n. sp. a, head; b, palpus; c, notopleural lobe; d, antenna; e, 
wing. Holotype. Fig. 5 Lepiselaga (Lepiselaga) crassipes Fab. a, palpus; 
b, notopleural lobe; c, antenna, Panama. 
