298 



ELEMENTARY STUDIES IN INSECT LIFE 



DIPTERA. 



A. Antennae with more than six segments, not ending in a 

 style or bristle; palpi slender and flexible, four- or five-jointed. 

 ( Orthorrhapha Nemocera. ) 



B. Dorsum of thorax with a distinct V-shaped suture. (See 

 Fig. 228.) Legs unusually long. Tipulidae. 



(Crane-Flies. 



FIG. 227. a, antenna of a Bombyliid ; ft, antenna of a Syrphid ; c, antenna of a 

 Muscid ; d, antenna of a Tabanid. Drawn from specimens, by Miss M. E. Wise. 



BB. Dorsum of thorax without distinct V-shaped suture. 

 C. Margins of wings and each of the wing veins fringed 

 with flat scales. Antennae with whorls 

 of hair or plumes ; plume generally 

 dense in male and sparse in female. 



Culicidae. 



( Mosquitoes.) 



CC. Margin of wing and each of wing 

 veins without fringe of flat scales; 

 antennae thick, straight, shorter than 

 the thorax. Legs comparatively short 



and stout. Bibionidae. 



(March-Flies.) 



AA. Antennae three jointed, with distal 

 joint marked with from five to eight rings 

 or annuli. Bristle when present is us- 

 ually at end, not on upper side of last 

 segment. Palpi one- or two-jointed. (Or- 

 thorrhapha Brachycera. ) 



B. Antennae three-jointed, the second joint usually short. Third 



segment frequently annulated. (See Fig. 227, d.) Tabanidae. 



( Horse-Flies.) 



BB. Antennas three-jointed, the terminal joint not distinctly 



FIG. 228. Thorax of 

 crane-fly, showing V- 

 shaped suture. (After 

 Comstock.) 



