NATURAL SCIENCES OF PHILADELPHIA. 163 



each side between mitklle and apex, apical segments dilated and 

 subcompressed. Length 3^ lines. 

 Orizaba. 



Subgenus Christolia, Ernlle. 



The form of the species belonging to this subgenus is robust, 

 especiall}- that of the head and thorax, the latter is gibbous, the 

 metathorax short and broad, with the tubercles short and blunt, 

 the legs more robust than usual, and the abdomen short, and broad 

 ovate in 9 ; areolet minute and open. 



Body black, abdomen silvery-sericeous at apex. 



Anterior wings with a median fuliginous subquadrate mark and apex 



dusky ; tibial spurs black 1. nubecula. 



Anterior wings hyaline, dusky only at apex ; tibial spurs white. 



2. calcarata. 

 Bod}^ black, marked with white or yellowish. 

 Posterior femora black above. 



Metathorax with two round yellow spots covering tubercles ; poste- 

 rior tarsi black beyond basal joint 3. zapotecus. 



Metathorax with two large subquadrate yellowish marks on jiosterior 



foce ; posterior tarsi entirely yellow 4. mirabilis. 



Posterior femora yellow, black only at extreme base and apex. 



5. mirandus. 



Body black, abdomen and legs red 6. abdominalis. 



1. Christolia nubecula, n. sp. 



9. Black, opaque, subsericeous, third and following segments 

 of abdomen strongly silvery-sericeous; annulus on antennae above 

 and apical segment of abdomen above, wiiite; wings hyaline, apex 

 dusk}', an irregular brown spot on middle of anterior wing, ner- 

 vures and stigma black; anterior tibiae and tarsi pale brown. An- 

 tennae nearly as long as bod^'^, apex robust; thorax strongly gib- 

 bous ; mesothorax with some longitudinal wrinkles on each side 

 of middle ; scutellum small, convex, smooth and polished, sides 

 strongly carinate ; metathorax large, broad, depressed behind, 

 reticulated, sides transversely striated, on each side above a short, 

 very obtuse tubercle, stigmata large and ovate; legs slender, pos- 

 terior pair unusually long; wings long, narrow, areolet small, 

 quadrate, outer nervure obsolete ; abdomen short, strongly arcuate, 

 first segment slender, nearly as long as all the remaining segments, 

 slightly and squarely dilated at tip, smooth and polished, stig- 

 inatic tubercles prominent and placed between middle and apex; 



