FAM. EMPIDID/E 13 
'The sexual dimorphism of B. serratula is most striking. Besides the genital differences, the legs 
of the male are curiously modified and even its neuration is changed. In this species some of the hairs 
of the hind margin of the wing are bent forward on the inner surface to form a long curved fringe. 
NOMENCLATURE 
Type species : B. vesiculosum, Fabricius (Pl. |, Fig. 2). Westwood in 1840 designated 
longicornis Meigen as the type, a species which Rondani later made the type of his genus Tvichopeza, but 
Blanchard, also in 1840, selected vesiculosum as the type of. Brachystoma, a procedure which has been 
since followed. 
There seems to be no satisfactory distinction between Brachystoma and Blepharoprocta. The latter 
group, as exemplified by binummus, has the marginal cell closed, the end of the female abdomen not 
inflated, the male legs distorted and there is a prominent fringe on the pygidium. None of these char- 
acters occur in Brachystoma. — However, in Roberisonti, which was described as a Brachystoma, the 
marginal cell is open, but the pygidial fringe is lacking and the abdomen of the female is narrow. In 
nigrimana, which Coquillett considered the type of Blefharoprocía, the legs are simple and the pygidial 
fringe is quite inconspicuous. I have a specimen of nigrimana lacking the fork of the third vein in one 
wing, showing that this character also is unstable.  Serratula and binummus are the female and male 
respectively of the same species.  Heterophlebus was proposed by Philippi shortly after the publication 
of Blepharoprocta, and was based on the same character, the closure of the marginal cell. 
Geographical distribution. 
SuBGENUS BLEPHAROPROCTA, LoEw 
I. B. ambigua, Philippi, Verh. Zool.-bot. Ges. Wien, Vol. 15, p. 764 [1865] Chile. 
(Heterophlebus). : 
2. B. melanogastra, Philippi, ibidem, Vol. 15, p. 764 [1865] (Heterophlebus). ^ Chile. 
B. nigrimana, Loew, Berl. Ent. Zeitschr. Vol. 6, p. 194: Cent. 2, no 17 E. United States. 
[1862] (Brachystoma); Melander, Trans. Amer. Ent. Soc. Vol. 28, 
p. 261 (1902). 
4. B. serratula, Loew, Berl. Ent. Zeitschr. Vol. 5, p. 319, Vol. 6, p. 194: E. United States. 
Cent. r, n? 23 [1862] (Brachystoma) ; Melander, Trans. Amer. Ent. 
Soc. Vol. 28, p. 262 (1902). — PI. 8, Fig. 77. 
binummus, Loew, Berl. Ent. Zeitschr. Vol. 6, p. 193 : Cent. 2, no 16 [1862] 
(Brachystoma) ; Melander, Trans, Amer. Ent. Soc. Vol. 28, p. 261, f. 91,92 
(1902). 
5. B. thoracica, Philippi, Verh. Zool.-bot. Ges. Wien, Vol. 15, p. 764 [1865] Chile. 
(Heterophlebus). 
SuBGENUS BRACHYSTOMA, MEIGEN 
6. B. bicolor, Bigot, Ann. Soc. Ent. France (6), Vol. 9, p. 13o (1889). Chile. 
—. B. distinguendum, Schiner, Fauna Austr. Dipt. Vo]. 1, p. 117 (1862) no 
description. : : 
7. B. fuscum, Philippi, Verh. Zool.-bot. Ges. Wien, Vol. 15, p. 763 (1865). Chile. 
8. B. leptidium, Philippi, ibidem, Vol. 15, p. 762 (1865). Chile. 
9. B. nemorale, Philippi, ibidem, Vol. 15, p. 764 [1865] (Heterophlebus). Chile. 
Io. B. nigricorne, Philippi, ibidem, Vol. 15, p. 763 (1865). Chile. 
II. B. obscuripes, Loew, Neue Beitr. Dipt. Pt. 4, p. 37 (1856). Sardinia. 
12. B. occidentale, Melander, Trans. Amer. Ent. Soc. Vol. 28, p. 260, pl. 8, W. United States. 
f. 89 (1902). 
