38 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
which closely resemble one another, the females of some being sepa- 
rated by minute differences. The male abdomen is short, flattened 
above, and densely silvery pollinose; the male genitalia are of the 
same general type. The antennae are of the same structure and gen- 
eral shape. The frons of the female has a large shining black cal- 
losity which fills nearly the whole space between the eyes. 
PSILOCEPHALA HAEMORRHOIDALIS (Macquart). 
Plate 6, figs 47 and 48; plate 13, figs. 171 and 172. 
1840. Thereva haemorrhoidalis Macquart, Dipt. Exot., vol. 2, p. 26. 
There has been some discussion as to what species Macquart was 
describing, as there are several species which might answer the de- 
scription. The writer has designated the form most common in the 
type locality, a species having a wide distribution over the Eastern 
States. Krdéber had no clear idea of the species, as he placed several 
forms under that name in the United States National Museum mate- 
rial; he intimates that P. haemorrhoidalis may turn out to be a syn- 
onym of Thereva nigra Say, and in his paper on the North American 
Therevidae writes the following: 
In the Wiener collection there are before me specimens (females) of Thereva nigra 
Say (which belonged to the Wiedemann collection and also bear his determination), 
which seem to belong to the above species (P. haemorrhoidalis). They are true Psi- 
locephalae, with bare face but thickly pilose palpi. If it is determined that Thereva 
nigra Say is a Psilocephala species, then must P. haemorrhoidalis be made a synonym 
of it. Coquillett wrote that Thereva nigra was a true Thereva. 
Larva.—Malloch gives a description of the larva® and figures both 
larva and pupa in the same publication. The larva is probably not 
distinguishable from the larva of P. frontalis new species. 
Pupa.—The rows of spines and thorns on the abdominal segments 
are arranged in a characteristic fashion, the other structures being 
about the same as in P. frontalis. The first abdominal segment has 
six evenly spaced slender spines across the middle of the dorsum; 
segments two to six have two short yellow spines on each side of 
the median line and on each side of this short and long spines (see 
figs. 171 and 172); on the seventh segment the spines are long and 
curved. Along the sides of the abdomen there are raised tubercles 
above the spiracles and below these a group of four slender spines. 
Type locality.—“‘ Carolina.”’ 
Type.—Presumably in the Museum of Lille, France. 
Below is given a description of what is considered to be this species: 
Male.—Length 6 to 7 mm. Black, almost entirely white pilose; 
frontal triangle silvery on the sides, with a narrow central wedge of 
shining black (fig. 48); the ocellar tubercle gray pollinose. Face sil- 
® Bull. Ill. State Lab. of Nat. Hist., vol. 11, art. 4, p. 334. 
