222 long's second expedition. 



thorax and scutel inrpunctured; wings hyaline, with a very slight 

 ochreous tinge, stigmata very distinct, and with the costal ner- 

 vures fuscous, the other nervures light brownish, the process of 

 the radial nervure continued transversely to the middle of the 

 disk of the wing, is not only extended from that point to the ex- 

 tremity of the wing, but also towards the base of the wing, ter- 

 minating in this direction at the first transverse nervure. [330] 



Length of the body nearly two-fifths of an inch. 



This species was also found in Missouri. 



HEDYCHRUM Latr. 



1. H. ventrale. Green polished; tergum tinged with blue; 

 antennae blackish at tip; venter bronze. 



Inhabits Pennsylvania. 



Antennae, excepting the first joint, blackish-brown; front im- 

 pressed; stethidium with dilated punctures; thorax in the mid- 

 dle between the wings, with a purplish shade ; wings dusky, 

 nervures fuscous; tarsi, excepting the basal joint, dark brownish : 

 tergum passing to bluish-purple towards the tip ; tip very ob- 

 tusely rounded, terminal segment longer than the preceding one : 

 venter entirely dull bronzed. 



Length more than one-fourth of an inch. 



2. H. dimidiatum. — Green polished; posterior half of the 

 venter bronze. 



Inhabits Pennsylvania. 



Antennae, excepting the basal joint, and palpi, brownish-black ; 

 front somewhat impressed ; vertex between the stemmata dark 

 purplish ; stethidium with dilated punctures ; thorax longitudi- 

 nally on the disk dark purplish ; wings dusky, nervures fuscous; 

 tarsi dark brownish ; tergum longitudinally in the middle slightly 

 tinged with bluish, ultimate segment less than half the length of 

 the preceding one ; venter green, posterior half coppery. 



Length nearly three-tenths of an inch. 



From the collection of Mr. William Wood. 



MYRMOSA Latr. [331] 



M. unicolor. — Black; abdomen with cinereous hair; meta- 

 thorax with an impressed line. 

 Inhabits North-west Territory. 



