Arr, 4. REVISION OF THE FAMILY THEREVIDAE—COLE. iAT 
THEREVA BOLBOCERA Osten Sacken, 
1887. Thereva bolbocera OsTEN SACKEN, Biol. Centr. Amer., Dipt., vol. 1, p. 162. 
The third antennal joint is onion-shaped, the frons with a pair of 
velvety black spots; the wings are described as densely variegated 
with spots. Judging from the description the antennae are like those 
figured for T. novella on plate 11. The species may prove to be a 
Psilocephala related to tergissa and acuta. 
Type locality.—Presidio, Mexico. 
Type.—In the British Museum. 
THEREVA CRASSICORNIS Bellardi. 
1861. Thereva crassicornis BELLARDI, Saggio di Ditterol. Messic., vol. 2, p. 88. 
This species has not been reported since described from Mexico. 
It is a black, yellow marked species. The first antennal joint is de- 
scribed as very long, thick, inflated in the middle, as in Dialineura, 
species. The legs and abdominal markings are as in 7’. fucata Loew, 
but no mention is made of markings on the wings. 
Type locality.—‘‘Mexico.”’ 
Type.—In the Bellardi collection, Turin, Italy. 
THEREVA RUFICORNIS Macquart. 
1840. Thereva ruficornis Macquart, Dipt. Exot., vol. 2, p. 25. 
The following is a translation of the original description: 
Black; antennae rufous; apex of abdomen rufous; wings hyaline, the spots fuscous; 
length 3.1; male. 
Face and anterior part of frons black; antennae—the two first joints reddish, the 
third missing; abdomen—seventh segment and sexual organs reddish; anterior legs 
reddish brown, tarsi brown, the others are missing; halteres black; wings hyaline; 
base and exterior border yellowish, veins brown, a small spot of brown at the base of 
second submarginal and posterior cell. 
This species which is placed by the side of the preceding in the collection of the 
Museum, closely resembles that species and is perhaps a variety of it, yet the differ- 
ences which distinguish the two are possibly specific. 
Carolina. Museum. 
Type.—Presumably in the museum, Lille, France. 
This species, Thereva nigra Say, and the following three species 
described by Walker, I have not been able to recognize in any of the 
material examined; no doubt these forms are known under other 
names. Walker’s types are in the British Museum and will in time 
be redescribed and the synonymy worked out; it is therefore well to 
give the original descriptions, as they are not easily available. The 
species are not included in the table of species as this would only 
cause confusion. Major Austin has kindly furnished notes on the 
types. Three of the species described in the genus Thereva belong 
