478 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



Synopsis of foregoing species of Trypoxylon. 



Males 1. 



Females 6. 



1. Clypeus with a narrow produced medial portion, which, when seen from the side, 



is at an acute angle with the face, see figure 23 ; Neotropical species 2. 



Clypeus without a narrow produced medial portion, see figure 12; Nearctic 

 species 4. 



2. Process of the first ventral segment very near base and not strongly hooked, 



see figure 24; hair of head above emargination of eyes and the thorax 



white leucotrichium Rohwer. 



Process of first ventral segment not as near base and strongly hooked, see figure 21; 

 pubescence of head ^nd thorax black 3. 



3. Apex of medial process of clypeus broadly rounded, process not carinate to the 



apex; mandibles black gandarai Rohwer. 



Apex of medial process of clypeus sharply angulate laterally and carinate nearly to 

 the apex; mandibles rufous mexicanum (Saussure). 



4. Second and third dorsal segments broadly depressed basally, the fourth dorsal with 



a transverse suture at basal fom-th; process of the first ventral segment robust and 



at the middle of segment basale Rohwer. 



Second and third dorsal segments not broadly depressed basally, the foiu-th dorsal 

 without a transverse suture; process of the first ventral segment distinctly basal 

 of middle and more slender 5. 



5. Produced part of the clypeus very broad, so the lateral tooth falls well outside of a 



line drawn tangent to the inner orbits; the lateral tooth of clypeus not as large or 



as sharp; wings with a strong purplish reflection poliliforme Rohwer. 



Produced part of clypeus not as broad, the lateral tooth falling well inside of a line 

 drawn tangent to the eyes; the lateral tooth large and sharp; wings with a bronzy- 

 purplish tinge politum Say. 



6. Pygidium broader, see figure 14; first segment rather shorter and ventrally slightly 



produced basally so to be undulating politum Say. 



Pygidium narrower, see figm-e 19; first segment longer and only uni-emarginate ven- 

 trally near the base 7. 



7. Third dorsal abdominal segment broadly depressed basally basale Rohwer. 



Third dorsal abdominal segment not depressed basally, although somewhat con- 

 stricted in some cases 8, 



8. Anterior lateral margin of clypeus so sharply angled at the side as to appear dentate, 



see figure 18; mandibles black; posterior tarsi with the apical joint 



white politiforme Rohwer. 



Anterior lateral margin of clypeus not sharply angled, rounded, see figure 20; man- 

 dibles rufous; posterior tarsi with the apical joint black; Neotropical species... 9. 



9. Head above the emargination of the eyes and the thorax with black or blackish 



pubescence mexicanum (Saussure) . 



Head above the emargination of the eyes and the thorax with white 

 pubescence leucotrichum Rohwer. 



TRYPOXYLON SAUSSUREI, new name, 



Trypoxylon mexicanum Saussure, Reise d. Novara, Zool., vol. 2, 1867, Hym., p. 78, 

 No. 4, pi. 4, fig. 45, not Trypoxylon alhitarse var. mexicana Saussure, same 

 reference, p. 77. 



