OF NATURAL HISTORY. 735 



nating before in a small triangular impression between the an- 

 tennae ; the whole head, excepting the vertex, occiput and antennse, 

 striate with close-set very small lines, which are rather longer 

 on the mandibles : wings hyaline ; nervures yellowish-brown ; small 

 cubital cellule none: anterior segment of the petiole deeply 

 striate [291] longitudinally each side, decidedly longer than the 

 second which is subemarginate above : abdomen oval, truncate 

 submarginate at base : pleura, striate like the head behind. 



Length over three-tenths of an inch. 



% Much more slender ; transverse incisure between the wings 

 more obvious ; segments of the petiole not so deeply divided. 



Length over three-twentieths of an inch. 



Neuter. Piceous, varying to black ; abdomen cordate, almost 

 always black. 



Length under three-twentieths of an inch. 



This species is very common in various parts of the United 

 States, even in houses, and may be observed, by every one, 

 going in procession. The radial cellule is slender and elongated, 

 the including nervures being nearly parallel ; the inner nervures 

 does not quite attain the edge. The first cubital cellule is hardly 

 larger than the discoidal cellule, the recurrent nervure of which 

 enters the first cubital at the middle. Second cubital extending 

 to the tip of the wing. 



2. M. CORRUGATA. — Honey-yellow J wings with three complete 

 cubital cellules. 



Inhabits Indiana. 



$ Body dark honey-yellow, almost piceous : antennae whitish ; 

 first joint not longer than the second and third together ; second 

 joint rounded, thickest : metathorax with two obtuse tubercles 

 instead of spines : wings hyaline ; nervures and stigma pale yel- 

 lowish ; second cubital cellule complete, nearly as long as the 

 first cubital and petiolated from the apical angle of the discoidal 

 cellule, which is oblong subquadrate ; the descending nervure 

 from the stigma enters the second cubital : abdomen, first [292] 

 joint somewhat gibbous at tip ; second segment rounded : feet 

 whitish. 



Length over three-twentieths of an inch. 

 9 Somewhat darker than the male; metathoracic tubercles 

 1835.] 



