1865.] 31 



black, two-thirds the length of the abdomen. Length 6] lines; ex- 

 panse of wings 10 J lines. 



Male. — Resembles the female, except that the basal joint of the an- 

 tennae beneath is dull yellowish, and the spines on the metathorax more 

 obtuse ; the abdomen is not so distinctly marked on the 2nd and 3rd 

 segments as in the female, and the 2nd segment is rufous instead of 

 black, which may be owing to immaturity ; the apical segments are 

 more broadly black at base than in the female. Length 6| lines; ex- 

 panse of wings 9jr lines. 



Collection. — Ent. Soc. Philad. Two ( $ ? ) specimens. 



Mesostenus flavescens, n. sp. 



Yellowish: face orbits, annulus o.i antennfe, lines on mesothorax, and scu- 

 tellum, whitish; wings hyaline; metathorax with two obtuse spines. 



Female. — Pale honey-yellow, shining; vertex blackish; the face, 

 broad orbits and clypeus, whitish ; antennae two-thirds the length of 

 the body, black, with a whitish annulus beyond the middle, basal joint 

 beneath pale ; mesothorax honey-yellow, the dorsal lines well impressed, 

 blackish, on the middle two longitudinal whitish lines interrupted by 

 the blackish dorsal lines: tegulae, a line before and a spot beneath the 

 anterior wings, a space behind the posterior wings, the scutellum and 

 postscutellum, and the carinas in front of the scutellum, whitish ; the 

 space on each side of the scutellum, blackish ; metathorax honey-yel- 

 low, finely sculptured and with two short, obtuse, whitish spines be- 

 hind, the elevated lines well defined, the anterior transverse carina 

 sinuate. Wings hyaline, slightly iridescent ; nervures fuscous ; areolet 

 minute. Legs entirely pale yellowish. Abdomen elongate, subdepressed, 

 shining, basal segment short, broad at tip, the peduncle short and ro- 

 bust ; apical margins of all the segments obscurely whitish, more obvi- 

 ous on the first segment ; ovipositor blackish, scarcely exserted. Length 

 3 lines; expanse of wings 5 lines. 



Collection. — Dr. J. Gundlach. One specimen. 



Mesostenus pusillus, n. sp. 



Yellow; spot behind antennfe, occiput, mesothorax, except two central lines, 

 most of pleura, and base of metathorax, blackish; hind legs and abdomen 

 honey-yellow ; wings hyaline, iridescent. 



Female — Head yellowish; a broad black stripe commencing behind 

 the base of antennae and extending back to the occiput, covering the 

 ocelli, and becoming confluent with the black color which occupies 

 nearly the whole of the occiput ; face slightly dusky ; antennae slender, 

 more than half the length of the body, pale honey-yellow. Thorax 

 shining ; mesothorax black, polished, the dorsal lines rather deeply 



