DIPTERA 863 



Family ANTHOMYIID^ 

 The Anthomyiids 



The anthomyiids are very common flies of which about five hun- 

 dred species have been described from North America. They are 

 somewhat similar to the house-fly in appearance but structurally 

 distinct. 



In this family cell R5 of the wings is very slightly or not at all 

 narrowed, vein Mn-2 extending in a nearly straight line to the margin 

 of the wing (Fig.1114) and not bent in its outer part towards the tip 

 of the vein R4+5 as in the house-fly. The hypopleural and often the 

 pteropleural bristles are absent ; and the proboscis is never adapted 



Fig. 1 1 14. — Wing of Lispa. 



for bloodsucking. The adult flies are found on leaves and flowers, 

 and are also often found on windows in our dwellings. 



The larval habits are variable. Most species live in decaying 

 vegetable matter; many live in excrement, and doubtless are convey- 

 ers of typhoid fever, like the house-fly or typhoid-fly. Several species 

 have been found to be the cause of internal myiasis, having been 

 taken into the alimentary canal with vegetables and continuing to 

 live there. A few species are parasitic within living insects. And 

 some attack growing plants. Among the latter are certain well- 

 known pests of garden crops. The more important of these are the 

 following. 



The cabbage-root maggot, Hylemyia brdssiccB. — This insect in its 

 larval state feeds on the roots of cabbage, radish, turnip, and cauli- 

 flower; it also attacks the roots of various weeds belonging to the 

 same family of plants. There are two or more generations of this 

 pest each year. The first generation infests the young plants; the 

 eggs of the second generation are laid late in June or in July; later 

 generations, if they occur, do but little harm. 



The most practicable methods of control of this pest are to protect 

 the seed-beds with a covering of cheesecloth in order to exclude the 



