ART. 23 REVISION OF MACEOCENTRUS MUESEBECK 37 



There is very little variation in color in this material, the entire 

 insect being rather uniformly yellow-ferruginous with only the 

 propodeum and first tergite sometimes weakly inf uscated. The num- 

 ber of segments in the antennae ranges from 50 to 56. 



24. MACROCENTRUS LASPEYRESIAE, new species 



Very similar to instabilis, utilis, and ancylivorus. The more im- 

 portant differences are discussed under those species. 



Female. — Length 6 mm. Head rather large, much broader than 

 thorax ; as seen from the side the head appears fully as thick antero- 

 posteriorly at the level of the lower eye margins as at the insertion of 

 antennae, the cheeks being broader than temples; clypeus not es- 

 pecially strongly convex, more than twice as broad as long ; distance 

 from clypeal f oveae to eyes less than length of clypeus ; face usually 

 nearly one and one-half times as broad as long, with well separated 

 punctures; longest segment of maxillary palpus longer than second 

 segment of antennal flagellum ; apical segment of labial palpus long ; 

 antennae much longer than the body, 53-segmented in the type. 



Thorax elongate; prescutum not especially prominent, rather less 

 strongly elevated and descending less abruptly anteriorly than in 

 related species ; notauli not distinctly f oveolate ; scutellum more than 

 half as long as propodeum; propodeum narrowing quite strongly 

 behind, finely granularly rugulose on basal half, except laterally 

 at base where it is mostly smooth, more or less transversely 

 striate apically; sides of pronotum and the pleura smooth, with 

 only scattered punctures; coxae smooth; apical teeth of trochan- 

 ters strong, conspicuous; trochanters of middle legs usually with 

 six or eight teeth ; radius arising from very slightly beyond middle of 

 stigma; radial cell long but not quite attaining extreme apex of 

 wing; metacarpus hardly extending beyond apex of radial cell; 

 submedian cell only very sparsely hairy; nervulus postf ureal by 

 nearly its own length; mediella much more than twice as long as 

 lower abscissa of basella, the latter not distinctly as long as nervellus. 



Abdomen a little longer than head and thorax combined; first 

 tergite more than twice as long as broad, with a distinct impression 

 at base, and entirely closely longitudinally aciculate, the spiracles 

 not distinctly beyond basal fourth and farther from each other than 

 from base of tergite ; second tergite not distinctly longer than broad 

 at apex, mostly finely aciculate, smooth apically, the depressed lat- 

 eral margins broad at base, the raised sculptured part of the tergite 

 broadening gradually behind ; third tergite smooth, with only faint 

 longitudinal lineolation medially; remaining tergites smooth; ovi- 

 positor sheaths as long as the body. 



