78 ILLINOIS BIOLOGICAL MONOGRAPHS (396 



caudal wing; setae with calices surrounded by minute brownish areas; giandubae 

 always sessile, sometimes microscopic, diameter never more than half the diameter 

 of calices of setae 2. 



2(3) Giandubae minute but distinct, about one-third as large as calices of setae or micros- 

 copic in smaller specimens; annulation, 1, (5, 6), 2, 3, 4; subspiracular area with 3-4 

 setae; surpedal area with 3-4 setae; larvapods with 2-4 setae as viewed from side; 

 head light brownish-green, marked with fuscous streaks on both sides of entire 

 length of epicranial stem, front with dorsal two-thirds light brown; following parts 

 light brown: labrum, antennae, mandibles, cervical sclerites, tarsal claws, and spir- 

 cles; body greenish, caudal segments pinkish or bluish, dorsal vessel dark green with 

 distinct fine white line on eash side; Length, 14 mm.; on Salix; Y- 143-2-2,-155, M-96. 



murtfeldtiae Marlatt. 



3(2) Giandubae microscopic, difficult to detect 4. 



4(5) Second annulet of abdominal segments always longer than either fifth or sixth 

 annulet; larvapods with about two setae as viewed from side; subspiracular areas 

 with 4-5 setae, surpedal areas with 4 setae; annulation, 1, (5, 6), 2, 4, 3; on birch; 

 M-24 Pristiphora sp. 1. 



5(4) Second annulet of abdominal segments always shorter than either annulet 5 or 6; 

 larvapods with 1-2 or 2-4 setae as viewed from side; subspiracular areas with four 

 setae; on alder or willow 6. 



6(7) Larvapods with 1-2 setae as viewed from side; annulation 1, 2, (4, 5, 6), 3; surpedal 

 areas with 3-5 setae; body green, cylindrical; head pale brownish-green, marked with 

 brown streak along entire length of epicranial stem and dorsal two-thirds of front 

 and vertex, narrowly dorsad of each ocellara; following parts brown: antennae, 

 labrum, mandibles, maxillary palpi, cervical sclerites, tarsal claws, and spiracles; 

 antennae conical, segment 4 short, conical; spiracle with cephalic wing distinctly 

 longer than caudal; setae without brown areas surrounding calices; giandubae 

 minute, sessile, microscopic; M-74 Pristiphora sp. 2. 



7(6) Larvapods with 2-4 setae as viewed from side; surpedal areas with 3-5 setae; annula- 

 tion, 1, 2, 6, 5, 4, 3; on wolly willow; M-90 Pristiphora sp. 3. 



8(1) Larvapods glabrous; antennae conical or limpet-shaped; head with or without a dark 

 streak dorsad of each ocellara; spiracles winged or not winged, if winged, wings 

 subequal in size, or cephalic wings larger than caudal; setae usually with calices 

 surrounded by minute but distinct brownish areas; giandubae sessile or stalked, 

 sometimes microscopic 9. 



9(10) Head distinctly and uniformly brownish; spiracles indistinctly winged; all setae 

 ventrad of subdorsal lines with calices surrounded by minute brownish areas; an- 

 tennae conical; giandubae subequal to calices in diameter; annulation, 1, 5, 6, 2, 3, 4; 



on birch; M-132 Pristiphora sp. 4. 



10(9) Head never distinctly and uniformly brownish 11. 



11(12) Body on dorso-meson from prothorax to fifth abdominal segment with a distinct 

 blackish line; spiracles winged, cephalic wings usually larger than caudal; all setae 

 ventrad of subdorsal lines with calices surrounded by minute brownish areas; an- 

 tennae conical; giandubae minute, about half as large as calices in diameter; head 

 with distinct line along epicranial stem; vertex without a dark streak dorsad of each 



ocellara; annulation, 1, 2, (5, 3, 4, 6) or 1, 2, (3, 4, 5, 6); on Prunus; M-128 



Pristiphora sp. 5. 



12(11) Body on dorso-meson from prothorax to fifth abdominal segment without a distinct 

 blackish line 13. 



13(14) Head entirely pale or light brown; vertex without dark streak along epicranial stem. 

 antennae distinctly conical; spiracles winged, wings subequal in size; setae never with 



