OF NATURAL HISTORY. 675 



THULEA Say. 



ArtiJidaJ Chai-acter. — Antennte six-jointed ; last joint clavate. 

 Radial cellule one. Cubital cellules three. 



Xatural Character. — The antennae are rather short, decidedly 

 clavate; first joint very short, not longer than broad j second 

 joint at least as long again as the first and somewhat more ro- 

 bust, cylindrical ; third rather longer than the 1st and 2d to- 

 gether, much more slender, cylindric, hairy; fourth minute, 

 shortest; fifth about the length of the third, subcylindric, [214] 

 naked ; sixth slightly longest, nearly equal to the 3d and 5th, a 

 little dilated towards the tip ; scutel large. 



Observations.— This is distinguished from the genera into 

 which Leach has divided Clmhex Fabr. by the number and con- 

 struction of the joints of the antennae, combined with the wing 

 cellules. It corresponds with Clavdlaria in its one-jointed club, 

 but has one joint more in its antennae, and only one radial cellule. 

 It agrees with Zarxa in the number of the joints of the antennae, 

 but not in the number which constitute the club, nor in the 

 number of radial cellules. With Pcrga it is related by the com- 

 parative magnitude of the scutel, and the number of joints of 

 the antenni, but differs remarkably in the proportions of the 

 latter, as well as in the number of cubital cellules. Pachyhsticta 

 of Klu-has a one-jointed club, but one joint less than the pre- 

 sent genus, and two radial cellules; and Syzygonia of the same 

 author, with a one-jointed club, has appendiculated radial cel- 

 lules. 



T. NIGRA.— Body black : nasus and labrum green : spot before 

 the wings, wing-scale and feet yellowish-green. 



Inhabits Mexico. 



Length to the tip of the wings three-twentieths of an inch. 



The smallest species I have seen of this family with clavate 



, [21 oj 



antennae. ■- 



1835.] 



