224 



DIPTERA OR TRUE FLIES. 



with a large yellow head, black eyes, and yellow legs; the 

 wings are iridescent, and the veins yellow. The flies appear 

 about the time the young carrots are up, and lay their eggs 

 close down upon the plants ; the young larvae coming from them 

 are long yellowish maggots pointed at the head end. They 

 are white when quite young, and at once eat their way into 

 the carrot, where they tunnel about at first under the rind, then 

 internally, and cause rusty patches to appear over their abode. 

 On pulling up a carrot showing outward signs of this attack, 

 one often finds several of these larvte half out of the carrot 



^ 



Fig. 113 — Carbot Flt (Psiln rosrr). 



1 and 2, larva, nat. size, and mag. ; 4, rusty carrot ; 3, enclosed larva ; 5 and 6, pa- 

 pjrium, nat. size, and mag ; 7 and 8, imago, nat. size, and mag (Curtis.) 



(fig. 113, 3 and 4) ; but they do not come right out until they 

 are ready to pupate, when they leave the tunnels and meta- 

 morphose in the ground The brown sausage-shaped puparia 

 (•5 and 6) are long and cylindrical and somewhat wrinkled ; from 

 the pupa inside the fly hatches in about three weeks. There 

 are several generations in the year — at least three according to 

 my observations. The gruhs may be found at all times, from 

 May until the carrots are lifted. When " rusted " the carrot 

 leaves turn prematurely yellow and red, and thus clearly 

 indicate the presence of P. rosa: These flies are undoubtedly 

 attracted to the young carrots by their smell, as we find in 

 Onion Fly, Turnip Flea, &c. It is especially after thinning 



