POTATO FROG FLY. 



171 



visited by this pest, immediate and certain measures of 

 destruction could be applied within a couple of days of receipt 

 of intelligence of its presence. 



Potato Frog Fly. Euptcnjx suhnti, Curtis. 



1 and 2, eggs ; 3 and 4, pnpa: ; 5 and C, Frog FJies, nat. size and magnitied. 



This insect feeds in all its stages by inserting its sucker into 

 the stem or leaf of the Potato, and drawing out the sap. 



The eggs (figured above) are white and shuttle- shaped, and 

 are to be found upon the under side of the Potato-leaves. 



The larva, which is much Hke the parent Frog Fly in shape, 

 but without wings, is green when hatched, and is furnished 

 with six legs, two horns, and a sucker ; in the next stage (the 

 pupa) it is green, nearly as large as the parents, but narrower; 

 with black eyes, long black horns, and a stout sucker, by 

 means of which it feeds until ready to change to the perfect 

 insect. It then fixes itself firmly by its six legs to a stalk or 

 leaf, the skin bursts along the back, and through the opening 

 the perfect insect creeps out, leaving the deserted case stand- 

 ing as an empty insect-skin on the plant, or fallen beneath it. 

 This "Frog Fly" is bright green, fading after death to a 

 yellow tint, with short horns, brown eyes, and four iridescent 

 wings less than a quarter of an inch in expanse ; the u^iper 

 pair glossy, somewhat rusty at the tips, and twice as long as 

 the body ; the lower pair exceedingly delicate. The length of 

 the insect is about a twelfth of an inch. 



The flies are very nearly allied to the common Cuckoo Spit 

 Fly {Tcttigonia spumaria), but they have not the power, hke 

 the Cuckoo Spit or " Froth Fly," of secreting a mass of frothy 

 matter round them in their larval stages. 



It does not appear that, as yet, this fly has been noted as 

 causing any serious mischief to Potatoes needing prevention 

 or remedy, and I have scarcely ever received enquiries as to 

 its attacks, but as it is sometimes very abundant on the plants 



