ART. 4. REVISION OF THE FAMILY THEREVIDAE—COLE. 5 
bristles. The third joint is quite varied, in some short and broad, 
usually as long as the first, in Henicomyia five times as long; in 
Ozodiceromyia it appears ringed and spinose. In the genus Dialineura 
and in certain species of Psilocephala the third joint is quite short, 
often with a more or less distinct basal annulation. The antennal 
style or arista is usually two-jointed and is more or less variable in 
shape, usually apical, but in some cases subapical or dorsal. In the 
genus Henicomyia there is apparently no style present. Coquillett 
and Kréber both overlooked the fact that there is a distinct style 
on the third antennal joint of Nebritus (a genus with one species); 
the style is not at the extreme apex of the third joint, but in a 
shallow dorsal pit a short distance from the tip. In the new genus 
Epomyia there is an approach to this form of antenna. 
Fig. 1.—MOUTH PARTS OF DIALINEURA CRASSICORNIS WILLISTON. A. OUTER MOUTH PARTS (DISTI- 
PROBOSCIS AND MEDIPROBOSCIS, WITH PALPI AND GALEA). 3B, INNER MOUTH PARTS (HYPOPHARYNX, 
EPIPHARYNX, BASIPHARYNX, OESOPHAGAL PUMP, ETC.). m, MEMBRANE; ™mpr, MEDIPROBOSCIS; 
th, THICKENING; the, THECA; ps, PPEUDOTRACHEA: dpr, DISTIPROBOSCIS; g, GALEA; St, STIPES: mz. pl., 
MAXILLARY PALPUS; fT. C., FRONTO-CLYPEUS; C7, CORNU; 0€. P, ESOPHAGAL PUMP; (0, TORMA; bph, 
BASIPHARYNX; S. b., SALIVARY BULB; l. ep, LABRUM EPIPHARYNX; hp, HYPOPHARYNX. 
The mouth opening is comparatively small and the proboscis and 
palpi small as a rule, but in Psilocephala the mouth parts are rather 
large. The mouth parts consist of the usually broad, fleshy, bilobed 
distiproboscis (see fig. 1A), which is grooved on the underside. 
Above this is a narrow chitinized connection surrounded by a mem- 
brane and the mediproboscis with a median thickening. The well 
developed, one-jointed maxillary palpi are connected with the pro- 
boscis, being fastened to the stipites, which in turn are fastened to 
the mediproboscis. The galea, not present in some families of the 
diptera, is narrow and needlelike. The mouth structure facing the 
