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tip^ making a very slight club, terminal joint but slightly longer than the pre- 

 ceding, and each joint with a few short hairs. The antenna reaches slightly 

 beyond the thorax and is composed of twelve joints. Sometimes the terminal 

 joint, when in a favorable light, appears to be divided into two. Thorax 

 polished and without parapsidal grooves or hairs. The mesothorax is notched 

 posteriorly, making the scutellum appear unifoveate. Scutellum smooth and 

 polished, and with a few scattering hairs, but no foveae. Abdomen short, 

 truncate, entirely black and polished. Ovipositor sheaths usually not visible; 

 when the ovipositor is exserted full length it is longer than the abdomen. 

 Wings 1.5 mm. in length ; radial nervure not reaching the costal margin ; 

 areolet large, but rather indistinct on account of the second transverse ner- 

 vure being very faint ; cubital nervure visible, nervures brown. Joints of legs 

 and tarsi brown, last joint of tarsi infuscate. Described from a large number 

 of flies that were reared from the galls in May. 



June Brood. Seven flies before me that came from the galls upon the 

 leaves in June, 1888, differ from the preceding by having more Hght colored 

 parts. The base of the mandibles, first three or four joints of the antenna; 

 and feet are distinctly lighter colored. In some cases the anterior tibiae and 

 the greater part of the anterior femurs are distinctly whitish, and the antennae 

 are distinctly 13-jointed. Only females were obtained. 



ON WHITE-OAK (Qiierciis alba). 



Acraspis niger n. sp. Galls. — Small, brown, globular bodies, 

 densely covered with a grayish pubescence which gives them the 

 appearance of felt on their outer surface, attached to the under sur- 

 face of the leaves of the white-oak in September and October. Galls 

 exactly similar are very common on the leaves of the bur-oak {Qicer- 

 cus macrocarpd), but from these I have not succeeded in rearing the 

 flies. Internally these galls have a fragile central cell surrounded 

 and held in place by a dense growth of dark brown radiating fibres. 

 The galls resemble very closely those in my collection of Acraspis 

 lanceglobuli Ash. 



Gall-fly — Female. — Color black, with a little reddish brown on 

 the thorax; thorax covered with a recumbent silvery pubescence; 

 abortive wings reaching the middle of the abdomen. 



Head entirely black, finely rugose, and with very few hairs. Antennas 

 r4-jointed, very dark brown or black, and 2.5 mm. in length. Thorax black, 

 with a little reddish brown above, covered with a recumbent silvery-white 

 pubescence, the hairs rising from minute punctures in a polished surface. 

 Scutellum small, finely rugose, without foveae, and covered with hair like the 

 thorax. Abdomen highly polished, with a small patch of silver>' pubescence 

 on the anterior inferior portion of the second segment. \'enter tipped with 

 a conspicuous tuft of yellowish gray hairs. Legs, except basal portion of 

 coxse, dark brown and densely set throughout with short gray hairs; aborted 



