12 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
without hair except as a fringe. The latter portion consists of two 
lobes which in a state of rest lie one above the other, the smaller 
anterior lobe folding back over the posterior. These are respectively 
the anterior (upper) and posterior (lower) calypters (PI. 3, fig. 20, tic, 
Ic). These are also called tegulae, squamulae, etc. Their free 
margins are fringed with whitish hairs which are longest at the angle 
formed by the fold, making a sort of tuft. It is so referred to in de- 
scriptions. 
The veined portion of the wing structure will be referred to as the 
wing. At its base are numerous small plates and articulating surfaces. 
It is impossible to say which belong to the wing and which to the 
thorax; they have been variously and arbitrarily designated (PL 3, 
fig. 20). 
For the terminology of the veins the system used is the commonly 
accepted one as given in Williston's Manual of the North American 
Diptera. Attention is called to the following points of especial 
interest. 
The very anterior base of the wing is concealed by a small projection 
of the thorax which ends in a chitinous plate, the tegula (PI. 3, fig. 20; 
PI. 4, fig. 24, if.). This, contrary to the opinion of Lowne, is homolo- 
gous with the tegula of Hymenoptera, as has been definitely shown 
by several morphological workers. Since this term has also been used 
for the calypters, the name 'epaulets' of Lowne (PI. 3, fig. 20, e.) will 
be used in descriptions. In this particular species it is light yellow 
and brown in color, the brown occurring at the basal part. Function- 
ally, it acts as a buffer to prevent the base of the wing, as it moves in 
flight, rubbing against the thorax. Lying between the tegula and the 
base of the costa is a somewhat larger, whitish, scale-like structure, 
the subtegula (PI. 3, fig. 20; PI. 4, fig. 24, st.; subepaulet, 5f.). This 
also is probably protective in function. 
The costal vein bears bristles for its entire length. These are 
largest toward the base. Other veins which terminate in the costa 
divide it into six sections. The section included between the ends of 
the auxiliary and first longitudinal veins is section III, that between 
the ends of the second and third longitudinal, section V (PI. 4, fig. 24). 
The length of these sections is approximately equal. On the costal 
margin, opposite the point at which the auxiliary vein meets the costa, 
can be seen the vestige of a stout bristle known as the costal spine 
(PI. 4, fig. 24, csp.). The base of the third vein is bristly about half 
