1916] American Species of Xylocelia 345 



SYNOPSIS OF THE SPECIES. 



FEMALES. 



1. Mandibles yellowish or whitish 4 



Mandibles entirely black 2 



2. Mesoscutum with the punctures sparse and indistinct on the posterior 



half; anterior half of front striato-punctate, the striae becoming more 



or less obsolete on the posterior half ater. 



Mesoscutum with punctures distinct and rather close throughout; front 

 with strong separated punctures 3 



3. All the tibiae and tarsi reddish brown, more or less testaceous beneath; 



nervures of anterior wings yellowish testaceous adamsi 



All the tibiae and tarsi black; nervures of anterior wings black nigritus 



4. Posterior lobes of pronotum yellowish 8 



Posterior lobes of pronotum entirely black o 



5. Posterior face of propodeum with a median, moderately deep, wedge- 



shaped fovea, the remainder of the posterior face finely, irregularly 



rugose 6 



Posterior face of propodeum without any wedge-shaped fovea, the entire 

 surface coarsely reticulate 7 



6. Apical antenna] joint with a strong longitudinal furrow beneath; all the 



tibiae testaceous; emargination of labrum broad and deep antennalus 



Apical joint of antennae not furrowed beneath, simple; all the tarsi more 

 or less blackish; emargination of labrum narrow, moderately deep. 



meta/horacicus 



7. Legs entirely black; head smooth, shining, sparsely punctate nwcriraniis 



Legs more or less testaceous; head not smooth, distinctly punctate; 



palpi light testaceous; labrum broadly and shallowly emarginate. .spiniferus 



8. All the tibiae yellowish or orange red, not black 9 



Middle and hind tibiae more or less blackish; wing nervures blackish 10 



9. Abdomen shining, with very close, fine punctures; nervures of wings 



testaceous occidentalis 



Abdomen shining, impunctate; nervures of wings black florissantensis 



10. Front rather densely punctate; abdomen distinctly petiolate gillettei 



Front sparsely but distinctly punctate; abdomen not distinctly petiolate, 



subsessile 11 



11. Postero-lateral angles of propodeum strongly produced; posterior face 



of propodeum finely, sparsely rugose, with a rather deep, median, 



wedge-shaped fovea striatus 



Postero-lateral angles of propodeum not strongly produced; posterior 

 face of propodeum rather coarsely reticulate siouxensis 



MALES. 



1. Mandibles yellowish or whitish 7 



Mandibles entirely black 2 



2. Posterior lobes of pronotum black 3 



Posterior lobes of pronotum yellowish; antennal joints 8-12 serrate 



beneath maestus 



3. Antennal joints not spined beneath 4 



Antennal joints 9 or 10-12 slightly spined beneath 5 



4. Abdomen microscopically punctate, appearing impunctate flavitarsus 



Abdomen punctured with strong, distinct, separated punctures cockerelli 



5. Mesoscutellum striated posteriorly; antennal joints 9-12 slightly spined 



beneath argentina 



Mesoscutellum punctured like the mesoscutum; antennal joints 10-12 

 slightly spined beneath 6 



6. Cheeks striato-punctate; propodeum indistinctly channeled above. .vallicolcB 

 Cheeks hardly striated; propodeum not channeled above, subsp. 



vallicolce salicis 



