ONION FLY. 



157 



These maggots may be found as early as May, whilst the 

 Onions are still very small, and the form of attack ascribed 

 by John Curtis and other writers to the Anthomyia ceparum 

 (now distinguished as the Pliorhia cepetorum, Meade), is stated 

 to begin by the fly laying her eggs on the leaves of the Onion 

 close to the surface of the earth, from which point the 

 maggots make their way between the leaves into the lowest 

 part of the Onion-bulb, where they may be found in numbers 



Onion Fly, maggot, and pupa ; magnified. Pupa in stored Onion. 

 Lines showing nat. size. 



varying from two or three upwards. Here these yellowish- 

 white legless maggots, of the shape shown magnified in above 

 figure, feed for a fortnight (or at least not for any length of 

 time) ; then they usually leave the bulb and enter the earth, 

 and there turn into chestnut-coloured pupa3 or fly-cases 

 formed of the hardened skin of the maggot, of the oval shape 

 also figured above. 



From these the fly comes out in from ten to twenty days, in 

 summer, and almost immediately lays her eggs, and thus 

 starts a new attack on the Onions which may have escaped 

 before ; and so the destruction goes on as long as any of the 

 Onions remain and the warm weather continues. 



The fly is figured magnified, with line showing nat. size in 

 spread of the wings, and as described by John Curtis. The 

 male is ash colour, with black bristles and hairs ; the face 

 white, with black horns ; three dark lines along the body be- 

 tween the wings, and a row of long blackish spots along the 

 abdomen; the female more ochreous or ashy grey, with 

 yellowish white face. The flies may be found throughout the 

 summer, but such of the maggots as turn to pups in the 

 autumn remain in that state till the following spring, and 

 then come out as flies in April or May. 



