ameri(;an diptera. 198 



and into an anterior and a posterior lobe that are shorter and com- 

 paratively thicker. Near the distal end of the inner surface each 

 pleuruni bears a small two-hooked process. This probably repre- 

 sents the two apical appendages. 



Amalopis inconstant O. S. 



The parts of the hypopygium are in general very similar to those 

 of the last species. The processes and hooks on the pleura, how- 

 ever, are distinctly ditlerent. The posterior or ventral distal angle 

 of each pleurum is elevated into a large rounded lobe. The ante- 

 rior or dorsal angle is produced into a lengthened spatulate process. 

 Within the latter is a large bifid process projecting forward, upward 

 and inward. 



Ainalopis ampla Doane (PI. IX, figs. 27, 28, 29, 30). 



The abdomen is cylindrical, the hypopygium forms a conspicuous 

 enlargement at the end. The eightii tergum is short, but the eighth 

 sternum is very long, being much produced posteriorly. On this 

 account the hypopygium is turned upward at an angle of about 45 

 degrees. 



The body of the hypopygium has no sutures between the tergum 

 and sternum. It is somewhat funnel shaped, the posterior rim being 

 wider tlian the base. The tergal part is produced posteriorly into 

 an oblong, semi chitinous plate ending in two points (fig. 29), and 

 reaching far beyond the lateral and ventral parts of the segnjent 

 (fig. 30). The sternal margin is widely emarginate (fig. 28). The 

 pleura are large, flat, oblong lobes rising vertically, or inclined foi'- 

 ward, from the rim of the genital chamber (figs. 30, 27). Each 

 bears at the distal end six large, hook like processes. In this species 

 the pleura are decidedly appendicular being attached by narrow 

 bases to the body of the hypopygium. 



Genus PH AL,ACRO€ERA Schiner. 

 This genus is described simply because it is representative of 

 Osten Sacken's Section VII, the Cylindrotomina. The hypopygium 

 is anomalous in some ways and its position in the series is not clear. 



Phalacrocera tipulina O. S. 



The hypopygium is somewhat box shaped. The tergum is a wide, 

 almost square plate, with a median linear notch behind. The chit- 



TEANS. AM. KNT. SOC. XXX. (25) JULY. 1904. 



