HOW TO KNOW THE INSEQS 



Fig. 218. Drosophlla melanogaster Melg. 

 (a. Adult; b, antennaT] 



Grayish brovm with dark markings on 

 thorax and tip of abdomen. Eyes bright 

 red. This Is the little fly so common 

 at fruit stands. It Is now used exten- 

 sively in studying genetics. Length 

 about 3 mm. (From U.S.D.A.) 



The members of this family are usually 

 under 5 mm. In length. They are found 

 Figure 218. wherovor overripe fruit or vegetables 



abound. Some feed on sap and fungi. 

 Their life cycle Is short and their multiplication rapid. 

 20a Vibrissae (Large bristles, one on either side of oral open- 

 ing) present (see Fig 212), though sometimes indistinct. Legs 

 moderate length. Abdomen with 4-5 segments. (The Fruit Flies.) 

 Fig. 219. Family 43, TRUPANEIDAE 



Fig. 219. Rhagoletls congulata Lw. The 

 ^Vhltebanded Cherry Fruit Fly. 



Blackish. Thorax with yellow margins, ab- 

 domen with white bands. Length about 5 mra. 



The adults of this family are frequently 

 found on flowers. The larvae live In fruit, 

 and seeds. Some are leaf miners. Others 

 make galls. The round knobs so frequently 

 seen on the stems of golden rod are made by 

 one of these files. 



Figure 219. 



20b Vibrissae absent (see Fig. 212). Legs short, abdomen with 

 5 or 6 segments. (The Pictured-Wing Flies.) Fig. 220. 



Fami ly 42, OTITIDAE 



Fig. 220. Delphlnla plcta . Fab. 



Head, thorax and abdomen 

 reddish brown. Eyes darker, scu- 

 tellum yellowish brown. Wings 

 opaque. In reddish brown and 

 white. Length 7-8 mm. 



In size these Pictured wing 

 files range from small to moder- 

 ately large. They are miost com- 

 mon In damp places. 



Figure 220. 



21a Metascutellum developed, 

 appearing as a strong con- 

 vexity below the scutellum 

 (a), hypopleura (h) with 

 strong bri sties . (The 

 Tachinids.) Figs. 220i and 

 221. 



Fami ly 79, TACHINIDAE 



Fif;. 220|^ 

 Thorax of a Fly. 



104 



