620 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



Ou the under side of the leaf it is much larger thau iu any of the 

 other leaf-galls, conical, either slightly narrowing apically or, more fre- 

 quently, slightly enlarged. The sides are vertical or nearly so; the 

 top broadly rounded without median depression or central nipple. 

 Size very variable ; averaging in height C to 7""", and in diameter at 

 base 4 to S""™. Color pale greenish yellow, with the tip more brownish ; 

 surface opaque, rugosely reticulate; at base often covered with a 

 whitish pruinescence, rarely with a few scattered hairs near the top. 

 (Fig. 202, a.) 



Fig. 202.— Gall of Pachypsylla c. ■mamma: a, leaf with 

 galls from underside — natural size ; b, section of gall 

 showing cuplike depression, and insect in cavity; c, 

 pupa -enlarged. (After Eiley.) 



The walls of the gall are hard and woody, at the bottom averaging 

 1.15'""', at the roof 0.75™°' in thickness. The cell (Fig. 202, b) is large, and 

 in cross-section much more 

 crescent-shaped than in the 

 preceding species. The ma- 

 ture pupa issues through an 

 oval slit sawed through the 

 roof, always near the side 

 where the wall is less thick. 



42. P. celtidis-puhescens n. 

 sp. — This gall on the upper 

 side of the leaf is represented 

 by a small circular cup-shaped 

 impression, surrounded by a rather wide, thickened, and elevated 

 margin, and furnished at the bottom with a small, usually star- 

 shaped, median nipple. The bottom and sides of the impression are 



Fig. 203. — Pachypsylla c.-mamma: adult— enlarged. 

 (Original.) 



