1937] Megamorphic and Mimetic Flies 117 
Chysidimyia chrysidimima new species 
Eyes nearly touching, approaching in an angular fashion 
which is but little over a right angle, perhaps 110 degrees. 
Eyes quite noticeably short, whitish pilose. Vertex swollen, 
the eyes gradually excavated behind so that the occiput and 
post vertex is for some distance rounded and enormously 
thickened. Ocelli inserted at highest point, some distance 
from post occipital margin and almost midway from an- 
tennae. Antennae situated a little above midline of profile, 
to the lower surface of a slight shelving prominence. The 
face below antennae slightly excavated for a short distance, 
then swelling to large rounded mammiform area and falling 
off just a short distance before the oral margin, not right 
at the margin. A marginal crease delimits the very small 
cheeks. Lower occiput very thin. There is a vertical crease 
down the midline of face. Antennae elongate, black, the first 
joint as long as the third; the second one-fifth or one-sixth 
of the third. The third is thickest just before the rounded 
apex. The arista is basally thickened, shorter than third 
and black and bare. Pile of face, except for a few dark hairs 
on front, whitish. Whole face and head everywhere deeply 
and remarkably punctate. 
Pile of thorax quite short, very appressed, black with a 
few pale hairs. Scutellum armed with two short spines set 
slightly closer than length of scutellum in midline. 
Abdominal pile short, scanty, appressed, black with a few 
pale hairs and in the margins more pale hair. The greatly 
thickened tergites at the sides are inrolled and the apical 
margin of the second segment is greatly thickened and 
equipped at the corners to overlap the rest of the abdomen 
in down folding. 
Legs black, the terminal tarsal joints dark brown; the 
tibiae and femora metallic green, with small punctures ; the 
hind basitarsi not extraordinary, nor the hind femora 
greatly thickened. Wings grey, terminal section of fourth 
longitudinal vein straight, a spur dropped from third longi- 
tudinal vein into the first posterior cell. Spurious vein 
present. 
Length 9 mm. 
One male. Santarem, Brazil, June 1919. (S. M. Klages). 
Accession 6324. Type in the Carnegie Museum. 
