March 1897.] DyAR : LaRV^ OF SaW-FlIES. 25 



nounced. A green elevation of the upper surface; below a thin skin, 

 not swollen, but slightly yellowish ; the leaf rolls over tightly in a close 

 coil to two whole turns, finally as far as the midrib, from one half to the 

 whole of one side of the leaf being involved. The little larva lives in 

 the gall, but soon comes out of it and rests in the rolled part. 



Stage II. — Head pale brownish, the eye black; width .3 ram. 

 Body all whitish, food forming a narrow green line ; slightly shining, 

 annulated, thoracic feet of good size. 



Stage III. — Head and anal flap shining black; width .4 mm. 

 Body whitish, slightly shining, annulate. 



Stage IV. — Head shining black ; width .55 mm. Body shining, 

 no distinct setae, irregularly 4- to 5-annulate; feet on joints 6 to 11 

 and 13. Body whitish, slightly opaque, food green ; the whole of anal 

 flap black ; anal prongs short, black. 



Stage V. — Head pale in the sutures, a large black patch on each 

 lobe and one in the clypeus; width .8 mm. Body 3-annulate, smooth, 

 not shining, whitish with a slight yellow-green tint, food green ; anal 

 end concolorous, no patch at all, though the frass gives a dusky shade. 

 Prongs very short, brown tipped. The larvte eat the parenchyma only, 

 as in the preceding species. 



Found on willow at Van Corilandt Park, New York City. 



Pteronus dyari Marlatt. 



<-- I supposed this species to have been bred from the same larvae 

 which produced Amaurofiematiis lufeotergum (Trans. Am. Ent. Soc, 

 xxii, 304), but Mr. Marlatt finds the flies distinct. Further observa- 

 tions are needed. 



Pteronus hyalinus Marlatt. 



c^.- I have described the larvae as Xematus lateralis (Trans. Am. Ent. 

 Soc, xxii, 307). 



Pteronus lombardas Marlatt. 



Larvae indistinguishable from those of P. ventralis, feeding on pop- 

 lar instead of willow (Trans. Am. Ent. Soc, xxii, 305). 



Pteronus populi Marlatt. 



Indistinguishable from F. hudsonii Dyar in coloration in the last 

 stage. 



Egg.—lw a cluster of saw cuts close together, but irregular, under 

 the lower epidermis at the apex of a leaf. 



Stage I. — Head .6 mm. Larvae all blackish. Gregarious, eating 

 holes in the leaf. 



