226 TEE AMERICAN NATURALIST [Vol. LVI 



male. In the former, the hairs are often clumped in a 

 compact mass on the anterior half of the thorax; while 

 in the male, the hairs are irregularly scattered over the 



whole area. The scutellum in the male (sometimes in 

 the female also) is blunt instead of pointed, posteriorly, 

 and the under portions of the thorax are consequently 

 visible. The wings are extended at an angle of about 

 45° to 90° in both sexes, and the veins are often faint, 

 short, and irregular, especially in the male. 



These flies are rather feeble and breed poorly except 

 in mass culture, probably on account of the many physi- 

 cal defects present. 



Origin. — Many males and females were found in a 

 stock culture of orange forked rough. Sister bottles 

 made up at the same time did not produce any deformed 

 flies. 



