ORTHORRHAPHA 



Nematocera 



Cecidomyidae 



Mycetophilidae 



Bibionidae 



Fig. 5. Ceciiifliiiyid tit-s/riictorSa.\. 2 '5 mm. The well- 

 known Hessian fly, destructive to wheat, especially 

 in the I'nited .States. 



Fig. 6. .Sc/itri! thoiiiiiL- Linn. 9 5'5 x 12 mm. 

 A gregarious fly, common on flowers 

 of Umbelliferae. The larvae feed on 

 plant-roots or on fungi and decaying 

 vegetation. 



Fig. 7. DilopJius jibtilis Linn. J 5 x 1 1 mm. 

 The F'ever fly, very common on L'mbelli- 

 ferae in May and June. The larvae are 

 injurious to the roots of garden crops. 



Figs. S, 9. Bihio iiiara Linn. i 7-5 x 16 mm. and 9 1 1 x 24 mm. St Mark's fly, appearing about St ^L-lrk's day 

 and abundant through May. The flies cluster on blossoms but do no harm. The larvae are injurious to roots. 



