6 PROCEEDINGS OP THE NATIONAL MUSEUM vol. 68 



Gqll (fig. 1). — A minute cell hidden in the tissue of the twig 

 under a leaf scar, the tip protruding so slightly as to be scarcely 

 noticed until the adult within begins to cut out a hole by which to 

 emerge. Sometimes two cells occur side by side under the same leaf 

 scar and more rarely the exit hole is just above the boundary of the 

 scar. They may be found in winter or spring in previous seasons' 

 growth usually underneath the scars just below the terminal bud 

 cluster. 



Biology. — On April 24, 1909, flies were found at Evanston, 111., 

 ovipositing on the buds of hicolor, perched on the side of the bud 

 with the ovipositor thrust perpendicularly through the bud scales. 

 Investigation revealed the galls described above in the leaf scars 

 under these buds with adults just emerging. In 1913 similar galls 

 were collected in Wilmette and insects reared. In 1915 they were 

 found again on April 17 when some adults had already gone and 

 one was seen ovipositing in a bud. On April 10, 1916, twigs con- 

 taining cells were collected and brought into laboratory and put in 

 water and by April 15 several flies had issued and three were seen 

 ovipositing in the side of buds in this indoor cage. By May 8 

 when the young leaves were over one-half inch long three small galls 

 were found from which the insects had already emerged and one was 

 found ovipositing in the axil of one of the young leaves. From 

 such scanty evidence and material no attempt is here made to de- 

 scribe either the adult or the gall of an alternating generation but 

 this may be suggestive to students who live where they can work 

 further on this life history. A precisely similar gall was found at 

 Ravinia on Q. alha after the adults had emerged. 



Habitat. — The type has been selected from the flies reared in 1913 

 at Wilmette, 111., where conditions are such that native trees of the 

 host oak will long persist. Paratypes are from Evanston and in- 

 clude those taken ovipositing as well as those reared. 



NEUROTERUS EVOLUTUS, new species 



Fevude. — Black with knees, front tibiae, and all tarsi brownish. 

 Head and thorax micro-coriaceous; head from above transverse, 

 cheeks broadened behind the eyes, occiput not concave; from in 

 front facial area broader than high, malar space one-third eye with 

 groove, antenna 13-segmented, lengths as (scape) 7:6:10:8:7:7:6: 

 6 : 6 : 5.5 : 5 : 5 : 7. Mesonotum shining, without trace of grooves. 

 Claws simple. Wing hyaline, pubescent, ciliate, veins distinct and 

 brownish, first abscissa of radius angled, intercubitus at angle of 52° 

 with basal, areolet reaching one-fourth way to basal, somewhat sym- 

 metrically placed beloAv apex, cubitus reaching basal on its lower 

 third, a faint cloud about break in anal and in first cubital cell. 



