ORrHORRHAl'HA 

 Nematoceka 



Cecidomyidae 



Mycetophilidae 



Bibionidae 



. 5. Ceddoiiiyiti destriiclor Sa\'. 2'5 nun. The well- 

 known Hessian fly, destructive to wheat, especially 

 in the United States. 



Fig. 6. Sciara thoiime Linn. ? 5'5 x 12 mm. 

 A gregarious fly, common on flowers 

 of Unibelliferae. The larvae feed on 

 plant-roots or on fungi and decaying 

 vegetation. 



Fig. 7. Dilophiis febrilis Linn. ? 5 x 1 1 mm. 

 The Fever fly, very common on Umbelli- 

 ferae in May and June. The larvae are 

 injurious to the roots of garden crops. 



Figs. 8, 9. Bibio marci Linn. 

 and abundant through May. 



cJ 7-5 X 16 mm. and $ 1 1 x 24 mm. Si Mark's fly, appearing about St Mark's day 

 The flies cluster on blossoms but do no harm. The larvae are injurious to roots. 



