58 
Psyche 
[April 
Adult, 
The adult fly is about the size of the common house fly» 
but it is much more gay in appearance. It may be seen on sunny 
days hovering about squash plants, or resting with half-spread 
wings upon the foliage of squash and upon certain wild flowers 
as well. It is strikingly colored, with deep reddish brown eyes 
on a head marked with black, gold and silver. The thorax is 
golden in front, with four longitudinal black stripes, clear black 
behind, and gray at the sides. The abdomen is of a brilliant 
orange color, except at the extreme tip, which is darker. The 
conspicuous abdomen, and the fringe of feather-like setae along 
the outer side of the hind tibiae, immediately catch the eye of the 
observer, and serve to make this species one of the most striking 
among Tachinid flies. 
A discussion of the adult anatomy is complicated by the 
diversity of terms which may be applied to the different struc- 
tures. Taxonomists have applied names which, in many cases, 
are morphologically inaccurate, and morphologists themselves 
have differed both in the nomenclature and in the interpretation 
of parts. The source of the terms used in this paper is indicated 
in the text of the different sections, and in many cases duplicate 
names for the various structures are given in the list of ab- 
breviations used in the figures. 
Head. PL 1, figs. 1 and 2. In describing the head, the 
terms used are those of Peterson (1916), except the chsetotaxy, 
which follows Coquillet (1897) and Walton (1909). 
Viewed from in front, the head is elliptical in outline, and 
broader than deep (3.2 mm. by 2.4 mm.). Its most conspicuous 
feature is perhaps the frontal suture (fs),^ which extends in a 
dark, shining, inverted U-shaped band from just above the 
insertion of the antennae to a point midway between the vibrissae 
(vib) and the curve of the compound eyes (ce), where it tapers 
out. Within the curve of the frontal suture lies the fronto- 
clypeus (fc), termed by Coquillett the ‘‘facial depression’’ and 
^Letters in parenthesis are those used in labeling the figures, and are 
explained in the list of abbreviations preceding the plates at the end of this 
paper. 
