ART. 23 REVISION OF MACROCENTRUS MUESEBECK 29 



nervulus postfurcal by about half its length ; submedian cell with a 

 hairless area apically; mediella nearly three times as long as lower 

 abscissa of basella, the latter a little shorter than nervellus. 



Abdomen not, or only indistinctly, longer than head and thorax 

 combined, a little narrower than thorax; first tergite not twice as 

 long as broad at apex, only weakly impressed at extreme base, del- 

 icately longitudinally aciculate, the spiracles before end of basal 

 fourth, the distance between them much greater than the distance 

 from spiracles to base of tergite; second tergite hardly as long as 

 broad at apex, delicately aciculate on basal two-thirds, the smooth 

 depressed lateral margins broad at base, the sculptured part of ter- 

 gite distinctly narrower at the base than at the middle; following 

 tergites smooth; ovipositor sheaths not distinctly longer than the 

 body. 



Yellow-ferruginous; head testaceous; palpi j'^ellow; antennae fus- 

 cous, scape and pedicel testaceous; thorax yellow-ferruginous; legs 

 yellowish, also the abdomen entirely; wings faintly dusky, veins 

 and stigma brown, the latter broadly yellow at base. 



Male. — Agrees with the female in essential respects; the antennae 

 are 48-segmented and the eyes a little smaller. 



Type.—U. S. N. M. No. 43505. 



Type locality. — Germantown, Pa. 



Allotype locality. — Glen Echo, Md. 



Paratype localities. — Falls Church, Va. ; Avon, N. J. 



Remarks. — Described from three females and one male. The type 

 was collected September 25, the allotype, September 19, 1920, by 

 J. C. Bridwell ; the paratype from Falls Church, Va., was taken by 

 E. A. Cushman September 24, 1918, while the other paratype was 

 collected on September 27, 1908. This last-mentioned specimen has 

 the antennae 45-segmentecl and the stigma mostly yellow. " ^' 



19. MACROCENTRUS ROBUSTUS, new species 



Closely related to ancylivorus, but distinguished especially by its 

 more robust form, the unusually broad first abdominal tergite, the 

 longer antennae, which are usually 50 to 54 segmented, and the some- 

 what broader face and clypeus. 



Female. — Length 1 mm. Head very strongly transverse, short 

 antero-posteriorly ; eyes prominent ; malar space a little longer than 

 basal width of mandible; face smooth, with only minute scattered 

 punctures; clypeus large, broad, more than twice as broad as long 

 and fully as broad as length of scape, rather strongly broadly 

 emarginate at apex; mandibles stout; longest segment of maxillary 

 palpus about as long as second segment of antennal flagellum; 



