616 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



not quite attaiiiiug apex of second abdominal joint, those of under wings slightly 

 projecting internally and posteriorly. Abdomen composed of eight joints, widest at 

 middle, gradually narrowing anteriorly and very strongly posteriorly ; anal joint 

 drawn ont in a horny process; first joint verj' short, second twice as long as the 

 first, the following threa joints still longer, the fourth being the longest and widest ; 

 dorsal and ventral sides of joints 2 to 4 separated by a rounded lateral bulging; 

 dividing sutures of segments 1 to 5 very deeply impressed ; last three joints much 

 less distinctly divided, more horny, and of darker color, rapidly narrowing posteri- 

 orly, and provided dorsally with a number of black, backwardly directed, triangular 

 teeth, arranged ;is follows: Sixth joint at middle of hind margin with two or three 

 very small teeth placed transversely and with no lateral teeth; seventh joint at 

 middle of hind margin, with a transverse row of four teeth, and on each side with 

 two or three (often obsolete) teeth or tubercles; anal joint with the horny process 

 about half as long as the joint, and nicked at the tip, while at base of process on 

 each side a lateral row of four small, closely placed teeth extends to the under 

 side, and finally on the disk of the joint three teeth triangularly placed, the poste- 

 rior being the largest; behind this group and just ab ove the base of the process is 

 another tooth nicked at tip. 



Tlie pupfB of the other species differ mainly from the above descrip- 

 tion in the smaller size, the form and length of the anal process, and in 

 the nninber and arrangement of the abdominal teeth. That of P. 

 G.-gemma alone has some other distinguishing characters. 



The young larvae of all species are of a more uniform pale color with 

 less developed wing-pads and the segmentation of the abdominal joints 

 much less evident; they are further distinguished by the smaller num- 

 ber of antennal joints and the weaker dev^elopment of the abdominal 

 armature. 



The galls produced by the species of Pachypsylia may be distin- 

 guished as follows: 



Polythalamous (very rarely monothalamous) galls, never on the surface of the leaf, 

 always singly. 

 Large gall on petiole and involving the basal portion of the leaf; usually some- 

 what reniform in shape, and with an opening near the tip. 



P. venusta O. S. 

 Smaller gall on the twig, bud-shaped, and without opening. 



P. c.-gemma Riley. 

 Monothalamous galls, always on the leaf, usually occurring in great numbers. 



Gall blister-like on both sides of the leaf and hardly raised above the surface of 



the leaf P. c.-vesiculum n. sp. 



Gall on the under side of the leaf, not blister-like, more or less raised above the 

 surface and assuming various shapes. 

 Gall on upper side of leaf, blister-like and not forming a depression ; on 

 underside of leaf star-shaped or flower-shaped.. P.c.-asimscHS n. sp. 

 Gall on upper side of leaf represented by a depression. 



Gall on upper side of leaf, with the outer rim alone depressed, the 

 central portion slightly raised and provided with a median spine; 

 on under side of leaf wart-like, much flattened, with a more or 



less pronounced depression at middle P. c.-umhiUcus u. sp. 



Gall ou upper side of leat represented by a cup-like depression, the outer 

 rim sometimes elevated. 

 Gall very large, mammiform without depression or rim ou top, 

 usually not pubescent, sometimes with slight down at base. 



P. c.-manuna Riley. 



