472 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



always taken above the water line but not far from it, are placed with 

 the hands or by means of a small hand shovel into the sieve and worked 

 over somewhat. As soon as the sandy constituents have been washed 

 away the Tabanid larva; become visible. The sieve need not be excess- 

 ively fine as even small larvaj instead of going through the meshes will 

 usually cling to the vegetable detritus, grassroots, etc., contained in 

 the mud. As Tabanids are rather common in some localities and the 

 larval stage, being of much longer duration than the imago, is more 

 likely to be found, it will usually take less than half an hour sifting on 

 any pond, brook or stream to find at least a few small-sized larvse. 

 One need not be discouraged about taking even the smallest ones as 

 the slowness of their growth has been much exaggerated; it is not 

 slower, for instance, than in many lepidoptera with a one-year's life- 

 cycle. 



For transportation, the larva? should not be placed in water but in 

 some wet material in which they can hide. Unless abundant food is 

 given, the larvse should be isolated because of their cannibalistic 

 habits. 



AN INFESTATION OF POTATOES BY A MIDGE ^ 



(DiPTERA, ChIRGNOMID^e) 

 By Edith M. Patch 



A record of a Chironomid larva, in the role of a potato miner, may 

 be of sufficient interest to justify transferring it from the notebook to 

 the printed page. 



On October 25, 1913, potatoes of the appearance shown in the 

 accompanying photograph were received from Roxie, Maine, with 

 the statement that they represented the condition of an infested acre. 

 The trails contained numerous dipterous larvce so different from any 

 pest known to the writer that it was at first suspected that they had 

 worked into mines made by something else and that their presence 

 was accidental. That such was not the case was testified by the larvae 

 themselves when a cut tuber was placed under the microscope. The 

 exposed miners were busily tunneling down into healthy tissue. As 

 they worked they moved the ventral flap under the head up against 

 the mouthparts. Some of the trails lay under the skin near the sur- 

 face of the potato and were apparent as soon as the tuber was washed. 

 Others extended for some distance into the vegetable, as is shown in 

 the figure of the potato cut in half. 



The larvse were three-sixteenths of an inch in length. They were 



1 Papers from the Maine Agricultural Experiment Station: Entomolgy 92. 



