HACKBERRY PSYLLIDS. - 621 



smooth and shining, and occasionally beset with a few scattered hairs; 

 the elevated margin is coarsely rugose-plicate, and usually also shining. 

 Average diameter of gall, including elevated rim, about 3"""; without 

 the latter, nearly 2'""^. On the under side of leaf it is usually semi- 

 globular, entirely sessile, sometimes more flattened, rarely more globu- 

 lar and then less sessile. Surface more or less rugose, not shining, 

 and covered with long but not densely placed white woolly hairs. 

 There is sometimes a small apical nipple surrounded by a slight de- 

 pression. Average diameter, 3""'". Color pale greenish-yellow. The 

 walls are very thin, but much thicker than the leaf itself; the roof is 

 straight and the cell comparatively large and crescent-shaped in a cross- 

 cut. Mode of issuing of mature pupa as in the preceding. 



43. P. celtidis-glohulus n. sp. — A gall on the upper side of the leaf 

 represented by a very circular hole with vertical walls near the top 

 and widening internally ; the rim is not thickened, but is vertically 

 elevated above the leaf surface around the opening. The walls and 

 bottom of the excavation are without decided sculpture and of a lighter 

 color than the leaf; the elevated rim is of the same color as and not 

 thicker than the leaf. Average diameter 1.75"^™. On the under side of 

 the leaf the gall is globular or slightly more pyriform and almost stylate, 

 or slightly more flattened and more sessile. There is a larger or smaller 

 shallow apical depression without central nipple, but sometimes limited 

 by a raised rim. Surface a little shining, finely rugose and not pubes- 

 cent, rarely furnished with a solitary hair. Average diameter 3.3"*™. 



I have only a single leaf covered with these galls received from 

 Columbia, S. C, collected in the month of September. No imago has 

 been reared therefrom. 



This is at once distinguished from the preceding species by the very 

 deep vertical impression on the upper side of the leaf and its globular 

 smooth form on the under side of the leaf. 



44. P. celtidiscucurbita n. sp. — This gall, on the upper side of the 

 leaf, forms a cup shaped impression, deeper than in P. c.-mamma., but 

 less deep and with the walls less vertical than in P. c.-globulus ; the 

 cavity is also not widened internally. The outer rim is not sharply 

 limited and not elevated except in one specimen, where it is thickened 

 and bulging as in P. c.-pubescens. The walls and the bottom of the cup 

 are not distinctly sculptured and of a greenish-yellow color (in dried 

 specimens), the rim being reddish yellow and rugose. Average diam- 

 eter, 1.75""". On the under side of the leaf it arises from a rather slen- 

 der, but not stylate, base and widens gradually to the middle, thence 

 gradually narrowing toward apex. When viewed from the side the 

 outline of the gall is therefore oval, but the top is always truncate. 

 The sides near the top are furnished with short ribs, which are sepa- 

 rated from each other by wide shallow depressions; the apex is formed 

 by an acute rim, which surrounds a cup-shaped depression varying in 

 size and depth according to specimens. Surface neither pubescent nor 

 shining, but finely and indistinctly strigose. Color (dried specimen) 



