ILLUSTRATIONS 



PLATES 

 Frontispiece Wilton Everett Britton 



Plate 1. Diptera 



1. Xcfhroioma fcrnigiuca Fabr. (Tipulidae). x 1 



2. Bibio albipcnnis Say (Bibionidea) male, female, and larva, x 4 



3. Asilus scriceus Say (Asilidae). x 2 



4. Bulb fly, Mcrodon cqucstris Fabr. (Syrphidae). x 2 



5. Microdon tristis Loew ( Syrphidae ) . x 1 



6. Apple maggot fly, Rluuinlctis pofiiourlhi Walsh (Trupancidae). x 2 



II. Diptera 



1. Housefly, Musca domcstica Linn. (Muscidae). x 5 



2. Parasitic fly, Tachina mcUa Walk. ( Tachinidae). x 2 



3. Parasitic fly, Winthcmia qnadrifynshtlata Fabr. (Tachinidae). x 2 



4. Stable fly, Muschui stahitlaus Fall (Muscidae). x 2 



5. Cabbage maggot, Phorbia brassicac Bouche (Muscidae). x 2- 



0. Green bottle fly, Lucilia sericafa Meigen (Metopiidae). x 1. Killed 



by fungus, on magnolia leaf. 



III. Gall-forming Diptera 



1. Cccidoinyia occllaris O. S. ( Cecidoniyidae). Galls on red maple. 



2. Honey locust pod gall, I>as\uciira ijlcditschiac O. S. (Cecidoniyidae), 



on honey locust. 



3. Pine cone gall, RJiabdopliac/a stroi'Uflides Walsh (Cecidomyidae), 



on willow. 



4. Ash midrib gall, Coiilnriniti caiuidciisis Felt (Cecidomyidae), on 



ash. 



5. Goldenrod ball gall, Eiirosta snlidai/iiiis Fitch (Trupaneidae), on 



goldenrod. 



6. Wheat ear gall, Rludnio/^luu/d Iriticnidcs Walsh (Cecidomyidae), 



on willow. 



1\ . Injtu'v to plants by Diptera 



1. Blotch mines of the spinach leaf miner. Pcgomyia hyoscyami Panz. 



(Muscidae). x 1 



2. Serpentine mine of the columbine leaf miner, PJiytomyca aquilcgiae 



Hardy ( Agromyzidae). x 1 



3. Larvae of pear midge, Contarinia l^yrivora Riley (Cecidom3'idae), 



in young pears, x 2 



4. Larvae of the cabbage maggot, Hylojiyia brassicae Bouche C Mus- 



cidae), injuring cabbage plant, x 1 



vm 



