38 E. T. CRESSON. 



Lemon-yellow ; disk of mesothorax black, with three or four quad- 

 rate yellow spots; flagellum fulvous 37. pulchra. 



Lemon-yellow; mesothorax with three black stripes; flagellum ferrugin- 

 ous 38. exoniafa. 



Posterior femora with six teeth; body luteous ; three marks on mesotho- 

 rax, large spot on scutellum, and breast, black. .39. COiiipactilis. 

 Posterior femora with numerous small teeth : 



Wings blackish, with hyaline tips ; body lemon-yellow ; mesothorax line- 

 ate with black; posterior coxas with broad black stripe above, their 



femora with two black spots 40. moil It czu ma. 



Wings hyaline or subhyaline : 



Posterior coxae yellow, bilineate with black: 



Luteous; posterior femora with two brown or black stripes on outer 

 side, the lower one near base oblique ; base of metathorax with two 



black spots 41. aztcca. 



Lemon-yellow; posterior femora with a single, short, slender, ob- 

 lique, black stripe on outer side near lower edge; base of meta- 

 thorax black, a central apical black spot 42. conjiuigeiiK. 



Posterior coxae black within and a slender black stripe at base on outer 

 side; mesothorax brown, with four yellow stripes; posterior fe- 

 mora yellow, with a broad central fulvous stain and a black 



apical spot 43. lenta. 



Posterior coxse lemon-yellow, with broad stripe above ; petiole of abdo- 

 men very short ; abdomen long, subfusiform, narrowly banded with 



black 44. lit a rise. 



Posterior coxse luteous, with a dusky stripe on inner side; scutellum 

 with a transverse black mark near tip; pleura with a broad ob- 

 lique black stripe 45. tolteca. 



Posterior coxa? lemon-yellow, with a rounded black spot on outer side : 

 Metathorax with a transverse black spot at base...46. iligropicta. 



Metathorax with a central elongate black spot 47. mirabilis. 



Posterior coxse luteous, with apical half black; scutellum immaculate; 



posterior femora luteous, immaculate 48. Gumlladiii. 



Posterior coxse lemon-yellow, black at extreme tips, femora with two 



black spots on outer side, confluent on lower edge 49. .ju via. 



Posterior coxse yellowish, immaculate : 



Pale luteous ; thorax with small blackish markings... 50. pallen*. 

 Pale lemon-yello.w, immaculate; abdomen cocciueous on apical 



half .". 51. delicata. 



Pale lemon-yellow, immaculate; abdomen tinged with rufo-testa- 

 ceous 52. iiiimaculata. 



1. ftmi vra microgaster. 



Chalcis microgaster, Say, Long's Second Expedition, ii, p. 326. 



Bab. — New York, Connecticut, Pennsylvania, The antennae are 

 long, robust, the scape more or less compressed at tip beneath ; the 

 four auterior legs more or less dull yellowish, the posterior femora not 

 so much swollen as usual, sometimes brown and generally more or less 

 tiuged with reddish-yellow at base, the teeth are numerous and minute ; 



