AMERICAN DIPTERA. 213 



chitin anteriorly. Two large lobes (fig. 78, h) arise from the niein- 

 braiKJUs areas veutrad of the pleural plates and hang downward. 

 These are not apical appendages, for they do not arise from the 

 pleura. The pleura are well developed as distinct plates set into the 

 posterior upper angles of the sternum (fij>. 78). 



There are only two apical appendages on each side. The first is 

 a simple clavate lobe rising vertically from the rim of the genital 

 chamber (fig. 79, A.). The second (B) is wide, flat, densely chitin- 

 ous distally, with the tapering end directed anteriorly. Covering 

 the basal three fourths of the anterior edge is the characteristic flat 

 elevation with free edges. 



The guard of the penis is a narrow shaft that expands distally 

 into a wide, flat, flaring, triangular plate. The latter ends in one 

 median and two lateral points, each bearing a decurved terminal 

 hook. 



Ti|>iila ciiieracea Coq. (PI. XIII, figs. 80, 81, 82, 83). 



The eighth segment is not specially enlarged. The seventh, 

 eighth and ninth segments form a large knob-shaped swelling at the 

 end of the abdomen. The hypopygium is directed posteriorly and 

 upward at an angle of about 45° with the axis of the abdomen. 



The tergum of the hypopygium is a simple transverse plate, emar- 

 ginate posteriorly, separated on each side by a distinct suture from 

 the sternum. The lateral sternal plates are separated below by a 

 narrow linear membranous area. Their anterior angles are connec- 

 ted by a narrow bridge of chitin with a slender, median, tapering 

 tongue of chitin running caudally in the membranous area back of 

 it. Each pleural lobe is large, rhomboidal and set deeply into a 

 notch on the side of the sternum. 



There are three apical lobes on each side, but only the first two 

 are well developed (fig. 8o). The first (A) has the ordinary clavate 

 form. The second (B) is larger and plate-like. It expands some- 

 what beyond the middle, and distally ends in a blunt point turned 

 forward. Most of its anterior edge is covered by a narrow lobe like 

 elevation. The third appendage (C) is a very small, simple, clavate 

 lobe arising from the outer side of the base of the second. 



The central vesicle is rather flat. The penis is also flat and strap 

 like. It is short and bends almost immediately downward from the 

 central vesicle. The guard of the penis consists of two longitudinal 



TRANS. AM. ENT. SOC. XXX. JULY. 1904. 



