8 PROCEEDINGS OF THE NATIONAl, MUSEUM. vol.60. 



elongate, confluent with the ocellar basin; antennal furrows nearly- 

 complete, only slightly interrupted opposite the lateral ocelli ; posto- 

 cellar line distinctly longer than the ocellocular line ; ocellocular line 

 subequal with the ocelloccipital line; postocellar furrow present, 

 straight, not broken by the faint furrow that runs to the anterior 

 ocellus; postocellar area sharply defined laterally, convex, without 

 punctiform foveae; frontal crest broken medianly; antennae and 

 wings as illustrated in the accompanying figures 5, 10, 23; sheath 

 broad, straight above, oblique to a sharp apex ; saw as illustrated in 

 the accompanying figures 36 and 42. Eeddish yellow; head, scape, 

 pedicellum, mesosternum, proepisternum, pronotum medianly, meso 

 and meta notum and apex of sheath, black ; wings yellowish hyaline, 

 strongly iridescent ; venation reddish yellow. 



Male. — Length 6.5-7 mm. Clypeus more densely punctured than 

 in the female, strongly convex basally, deeply, arcuately emarginate 

 anteriorly, the emargination in outline is approximately the same as 

 the outline of the lobes; supraclj^peal foveae deep, punctiform, the 

 rest of the head agreeing well with the female except that the middle 

 fovea is smaller, and more sharply defined and is in a broad depressed 

 area; antenna as in figures 9 and 24; hypopygidium nearly truncate. 

 Color as in female. 



Described from specimens from Canada and New York. 



Oviposition. — Eggs are deposited in cuts in the petiole of the leaves. 

 Lintner has counted twenty-eight to thirty scars in one petiole. 



Larva. — Length of full fed larva 16 mm. Head blackish and 

 brownish excepting clypeus, antennae, and ventral mouthparts which 

 are yellowish (figs. 49, 53, 54). Body yellow, large black spots in 

 supraalar and smaller ones epipleurally (figs. 71 and 57). Annu- 

 let A pale, without prominent areas and with pairs of small hairs, 

 usually two, situated subdorsally and in supraalar region. Annulets 

 B and C larger than A and D and with more spines, spines grouped 

 somewhat upon slightly prominent areas which arrange themselves 

 in a transverse row across the tergum. Annulet D is quite small, 

 indistinct, pale, and without spines. Epiproct with a single trans- 

 verse black splotch. 



Cocoon. — Length 14 mm., width 7 mm. Dark brown and translu- 

 cent, papery, somewhat shining, outline irregular. 



Host. — American Records : — Carolina Poplar and Poj)ulus monUi- 

 fera. European Records : — Populus pyramidalis (according to Ratze- 

 burg) ; Populus monilifera (according to Bouche) ; Populus alba 

 and Populus dilatata (according to Ondemann) ; Salix caprea (ac- 

 cording to Enslin). 



Seasonal History. — Gregarious feeders, eating the entire leaf, ex- 

 clusive of the midrib and larger veins. This species has apparently 

 two generations, the first appearing in June and the second in Au- 



