No. 423.] REMARKABLE OCCURRENCE OF THE FLY. 185 
Prothoracic spiracles low, not elevated above the thoracic dorsum; no 
respiratory horns or trumpets. 
Ninth abdominal segment terminating on the dorsal side in a pair of 
stout divergent triangular processes, that are about as long as the segment 
which bears them. 
The rather generalized larva is characterized by an unusually 
well-developed head, simple mouth parts, rings of tubercles on 
all the segments, those of the two hindmost segments elongate, 
becoming filaments, showing out of what material the borders 
of the tipulid caudal respiratory disk have been made. The 
pupa is characterized by the unusual brevity of the antenna 
cases, which reach but halfway across the eyes, distinctly 
paired jaws, low prothoracic spiracles without respiratory 
trumpets, horns, or tubes, and a naked, spineless skin. 
