62 The American Naturalist. [January, 
segment, with a transverse row of several hairs on each side of dorsum 
extending below on edge of venter, discontinued in middle on dorsum, 
slightly approximated to posterior margin of segment. Eighth or 
anal segment narrow, same width as posterior margin of seventh, nearly 
as long (to base of horns) as wide, terminated by three pairs of anal 
horns; anterior or upper pair short, small, situated at base dorsally of 
middle pair; middle or second pair long, curved slightly upward ter- 
minally, nearly as long as length of segment, widened inwardly on 
basal half so that the bases are closely approximated, inner outline 
hollowed out on apical portion, longitudinally corrugated at base 
above, with a dorsal longitudinal groove widening to hollowed portion 
and then extending narrowly to tip, moderately sharp at tips; third 
or inferior pair short, small, hardly as large as anterior pair and not so 
stout at base, directed more downward than middle pair, situated on 
outer base ventrally of middle pair ; just anterior to first pair on dor- 
sum there is a median very small spinous tubercle, apparently a rudi- 
ment (or herald) of a fourth pair of anal horns. Prothoracic spiracle 
situated on lateral front border of thorax (prothorax) just anterior to 
wing bases, mesothoracic spiracle not apparent, metathoracic spiracle 
situated anteriorly on lateral edge of dorsum of scutellar segment; 
first to sixth abdominal pairs of spiracles situated on anterior edge 
laterally of dorsum of first to sixth abdominal segments ; seventh pair 
situated one on each side of dorsum of seventh segment immediately 
behind the transverse row of hairs. It is interesting to note that a 
quite long section of the trachez is left attached in most cases to the - 
spiracles on inside of the pupal skin, especially to the thoracic pairs. 
The fly escaped by the pupal skin splitting along the dorsal median 
line of the head and thorax, the slit extending slightly into the scutel- 
lar segment; also splitting laterally backward on each side of head 
from a little above the base of anterior cephalic horns along what 
would nearly correspond to the frontal fissure in Muscide, the break 
curving shortly and obliquely upward to thoracic suture, and allowing 
the nearly triangular posterior dorsal or upper section of the integu- 
ment of the head to become loosened laterally below from its junction — 
with the thorax, and hanging like a flap by its median dorsal junction. 
Length, 93 mm.; width of basal abdominal segments, 2} mm, 
The anal extremity of this pupal skin is distended with a dirty 
colored hardened fluid ventrally, just below and anterior to anal 
horns, into a large round tubercle with a subcentral deep pit or orifice- 
like depression which is approximated to posterior margin, the anterior 
portion of the tubercle being greatly bulged and distended. The 
