HOW TO KNOW THE INSEaS 



13b No spurious vein, anal cell short 

 or wanting 14 



14a Frontal lunule (a crescent shaped 

 sclerite just above antennae) 

 present. Fig. 212 16 



Fig. 212. Diagrainmatic front view 

 of head. 

 14b Frontal lunule whol ly absent. 15 



15a Second basal cell always united 

 with discal cell to form one cell; 

 anterior cross vein small and not 

 more than one-fourth the length of 

 wing from its base* small, usually 

 metallic green or blue flies. (The 

 Long-Headed or Long-Legged Flies.) 

 Fig. 213. 



Fami ly 34, DOLICHOPIDAE 



■YlYXC^. 



vibrissde 



Figure 212. 



Fig, 213. Sciapus sipho Say 



Bright metallic green; legs, eyes 

 and spots on v/lngs blackish. Length 

 5-6 mm. 



These flies are small, almost al- 

 ways under ten millimeters in 

 length. Most of them are metallic 

 green or blue, and have- longer legs 

 than the other related families. 

 They feed on smaller insects and 

 mites. They are found in a rather 

 wide range of habitats and are rep- 

 resented by many species. This 

 would seem to be a good family for 

 some enthusiastic amateur collector. 



15b Anterior cross vein well beyond the basal fourth of the 

 wing, or the second basal cell complete; anal vein never reach- 

 ing the margin, sometimes wanting. (The Dance Flies) (in 

 part) See Fig. 210. Family 33,EMPIDAE 



16a Squamae (whitish scale-liice lobe 

 betow base of wing) large. Fig. 

 214 



Figure 213. 



21 



16b Squamae small or absent 17 



ITa Mouthparts vestigial; hidden in a 

 small oval opening. (The Horse Bot- 

 flies.) Fig. 215 



Family 75, GASTROPHILIDAE 



Figure 214, 



102 



