REHN AND HEBARD 07 



greatly swollen, narrowing sharply below the tympanum which organ is 

 apart, median tibiae expanding slightly proximad. Caudal femora long, 

 with genicular lobes produced in long blunt teeth. 



Allotype here selected: 9; Yucatan. (Schott.) [Hebard 

 Collection.] 



Description of Allotype. — Quite similar to type in size and general appear- 

 ance. Tegmina reaching the distal extremities of the caudal femora. Ovi- 

 positor similar to that of tolteca, except that it is somewhat less broad, as 

 in /. gracillima; subgenital plate of the same type as found in grncillima.'^' 

 Measurements (in millimeters) 



cf Temax, Yucatan. 

 Type..'. 



cf Castillo, Nica- 

 ragua 



9 Yucatan. Allo- 

 type 



9 Aspinwall, Te- 

 huantepec, Mex. . 



16.8 

 17.5 

 17.5 



M a> 



a I 



28.1 

 28.5 

 27.8 

 28.9 



2.9 



2.8 

 2.4 

 2.4 



4.9 



The above measurements show that there is some variation in the present 

 species and larger series may eventually prove it to be a geographic race of 

 I. gracillima, to which species it is closely allied. 



Color Notes. — General color of body and antennae pale russet, 

 shading to wood brown on limbs and organs of flight, the latter 

 obscurely marked with darker shades. Median segment and first 

 four dorsal abdominal segments marked on each side with seal 

 brown, thus forming two somewhat arcuate dark bands, somewhat 



trigonal spines on the ventral margins of the cephalic femora is 5-2 on the 

 cephalic, and 0-0 on the caudal margins, these spines irregularly distributed. 

 Unfortunately Saussure and Pictet have used this as the character to separ- 

 ate the present species from /. gracillima, in their key in the Biologia giving 

 the difference as 2 trigonal teeth for /. phthisica and 3-4 small spines for 

 gracillima. Our series of gracillima show a range of 3-1 on the cephalic; and 

 0-0 on the caudal ventral margins of the cephalic femora, while phthisica 

 shows a range of 5-1 and 0-0 on these margins. 



-" In the allotype this plate is somewhat shrivelled, owing probably to the 

 fact that the specimen was once preserved in alcohol. 



TRANS. AM. ENT. SOC, XL. 



