DIPTERA. 



489 



FIG. 1080. Tnchocera hiemalis. 



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 

 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-tirne. Gnats, and all 

 other dipterous insects, have no stings 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. 1081), and then eat the 



FIG. ioSi. Celery affected with 

 leaf- mining Larvae. 



FIG. 1082. 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. 



