SUPERFAMILY TINEOIDEA 121 



times the leaf is cut and a cone made from a pointed flap of 

 it. Some larvae feed on the upper surface and bend the 

 tip upward while other species cause it to bend downward. 

 The pupal case is a stout cocoon of silk spun within the 

 shelter of this cone. 



The willow-leaf cone-maker, Gracilaria stigmatella. The 

 young larvae of G. stigmatella separate the upper cuticle of 

 the leaves of willows or of poplars. They make at first a 

 short linear mine and then a blotch somewhat toward the 

 tip of the leaf. In later life the larvae emerge and by means 

 of silk draw the tip of the leaf upward and over until it lies 

 on one margin and forms a triangular fold or cone. Thus a 

 sort of spiral is begun. Especially in the willows with 

 slenderer leaves a helix of three coils may be formed involv- 

 ing the whole leaf to the base. The larvae live in these 

 shelters and feed on their inner surfaces. These later stage 

 cylindrical larvae are very like other free-feeding larvae in 

 form but perhaps have a somewhat narrower head. They 

 are uniformly greenish-yellow in color even to the segmental 

 appendages and attain a length of 6 to 7 mm. 



Often they pupate in the cone but sometimes they go to 

 the ground where they envelop themselves in a dense semi- 

 transparent web. 



The box-elder leaf-roller, Gracilaria negundella. This is 

 one of the most common and widely distributed members of 

 its genus. It is known at least from Colorado to New 

 Jersey. Its range has doubtless been extended in the East 

 by the extensive planting of this tree for shade and orna- 

 ment. Some of the trees observed by one of us (Mrs. Tot- 

 hill) in Lake County, Illinois, in the summer of 1916 seemed 

 to have one or two mines in every leaf. It has at times 

 been reported as very abundant in Missouri. 



When the minute flat-headed, flat-bodied larvae of this 

 moth begin to mine they separate the upper cuticle from 

 the parenchymous tissue in a contorted linear tract hardly 



