DIPTERA. 



489 



broccoli, and in all probability cause the plants to produce them. Fig 



1080, No. I, shows the small larva. which lives in this deformity, No. 2 



the same magnified; Nos. 3 



and 4 represent the pupa, No. 5 



the winged insect in repose, 



and No. 6 the creature in the 



act of flying. 



There are other gnats which 



appear sometimes in little 



clouds; and in the hot summer f.g. loso.-xrichocera hiemaiis. 



of 1870 many mosquitoes, the bites of which were very severe, visited 



our neighbourhood, and probably located themselves on the Sewage 



ground. At my garden some species constantly come out at dusk, 



after the midges have tormented us in the day-time. Gnats, and all 



other dipterous insects, have no sting at their tails like wasps, but bite 



with their mouths (fig. 1019, b, c). 



" When the sun shines, let foolish gnats make sport. 

 But creep in crannies, when he hides his beams." 



Shakspeare, Comedy of Errors. 



The celery and parsnip — but particularly the former — have been most 

 seriously injured by the great Celery Fly {Tephritis onopordinis). The 

 larvae live between the surfaces of the leaf (fig. 108 1), and then eat the 



Fig. ioSi. —Celery affected with 

 leaf-mining Larvae. 



Fig. ioSz.— Carrot Fly. 



intermediate tissue, so that the leaf cannot perform its functions, and 

 thus the whole plant is damaged and is liable to rot. The only 

 remedy is to pluck off the diseased portion of the leaf. 



