OF NATURAL HISTORY. 717 



of the thighs, the scutel differs from that of the preceding spe- 

 cies in being rugose, or with about five elevated Hnes, and its ter- 

 minal spine is much broader at the base and less conic. 



3. D. IMPATIENS.— Black : feet ferruginous : scutel mutic. 

 Inhabits Indiana. 



Body black, polished, obsoletely tinted with piceous : antenna; 

 pieeous-blackish : mandibles ferruginous : scutel with the mar. 

 gin deeply depressed and rugose : the disk elevated, oval, with 

 an acute edge, within which, on the posterior half, is an indenta- 

 tion and a more slight indentation before it, each side of which 

 are two or three punctures : wings hyaline, nervures pale brown : 

 abdomen acute at the tip of the tergum : feet ferruginous or rather 

 piceous. 



Length three-twentieths of an inch. 



4. D. PEDATUS. — Black : feet yellowish : antennae piceous : 

 third joint long. 



Inhabits Indiana. 



Body polished, impunctured, black : antennae yellowish-piceous : 

 first joint not much longer than the second : third joint much 

 longest, equal to the fourth and fifth together, and a little arcu- 

 ated : remaining joints subequal, [268] oval-cylindric : nasus 

 with a longitudinal indentation each side before : mandibles pi- 

 ceous : thorax without dorsal grooves, but a simple one over the 

 wings : wings with a very slight obscure tint : nervures brown : 

 feet honey-yellow. 



Length % less than one-twelfth of an inch. 



Differs from the two preceding species by the elongated third 

 joint of the antennae. 



5. D. STIGMATUS. — Black : feet yellowish : wings with a large 

 stigma. 



Inhabits Indiana. 



Body polished, black : antennae piceous : basal joint yellow- 

 ish : second joint closely [united to the first, shortest, almost 

 spherical : second and third joints subequal : wings hyaline, 

 nervures yellowish : stigma large, triangular : abdomen dull ru- 

 fous : feet pale honey-yellow. 



Length about one-twentieth of an inch. 



1835.] 



