ORTHOPTERA— ACRIDII. 221 



TYRBULA gen. nov. {Tvpftrj). 



Tin's name is proposed for a gronp of Truxalidae evidently falling in 

 close proximity to Syrbnla Stal, having linear antenna?, enlarged apically, 

 and hind tibiae well provided with spines. The antenna? are more distinctly 

 c'lnl)bed than in Syrbnla, the clnb being abont twice the diameter of the 

 stalk, composed of seven or eight joints of which the last two are very small, 

 forming a rapidly tapering tip. The head is less prominent than in Syrbula 

 and the eyes considerably smaller, being considerably shorter than the in- 

 fraocular parts of the cheeks ; otherwise the general aspect of the insect is the 

 same. The genicular lobes are as in Syrbula. The hind tibiae are abun- 

 dantly spined, in one species even much more abundantly than in Syrbula. 



TiMe of the species of Ti/rbula. 



Spines of bind tibije exceedingly numerous, their basal half hardly tapering 1. T. muUispinosa. 



Spines of hind tibiae less numerous, tapering uniformly throughout 2. T. russelli. 



1. Tyebula multispinosa. 

 PI. 17, Fig. 13. 



This species is represented mainly by fragments of hind wings and hind 

 legs. Of the former nothing more can be said than that they appear to have 

 had a faint smoky tinge with numerous black, delicate veins, and that when 

 closed they extended a very little beyond the tip of the abdomen. The 

 hind legs are long, moderately slender, the tibia? armed with exceptionally 

 numerous spines which are blackish, of uniform width to beyond the middle, 

 and then tapering, mainly by the excision of the under edge, giving them a 

 slightly upturned appearance, five or six times longer than their breadth at 

 the middle, and so closely set that the interspaces and the spines are of equal 

 breadth ; they decrease in length very regularly toward the base of the 

 tibia and to a slight extent toward the apex ; but just how many there are 

 or how far they extend toward the base the imperfect nature of the only 

 specimen preserving the tibia forbids determining ; it seems probable, how- 

 ever, that the number exceeds twenty-five. The specimen from Florissant, 

 preserving the femur, is placed here because its size agrees perfectly with 

 the other specimens and its form indicates the relationship. If it is correctly 

 placed, the femur is stouter and less delicately attenuated than in the next 

 species. 



