1918.] 229 



but the DerMni and Rhotanini are more difficult to define and have 

 onl}" three or four genera each. Zeugma Westw., which I place in the 

 Derhini, has little or no affinity with the other two genem ; the genei-a 

 under Rhotanini are all nearly related. 



Symidia is of interest, as its tegmina have the first median sector 

 with three branches (the neuration approaching the cubital system of 

 armngement), thus leading to the Dej^bini ; the wings are slightly less 

 than half the length of the tegmina, and the anal area is not greatly 

 developed (although there are two cubital veins), Symidia in this respect 

 leading to the Zoraidinae. 



It is interesting to note that none of the Zoraidinae have been 

 reported from the American continent or the West Indies, and the two 

 genera, Derhe Fabr. and Mysidia Westw., are confined to America south 

 of the United States and to the West Indies, with the exception of one 

 species in Australia. 



The four sections can be separated by the following characters : — 



a\ The cubital veins ending in the hind margin of the tegmen, the claval cell 

 closed, or if narrowly open then the claval vein reaching- no further 

 thau the last cubital vein. 

 b^. Cubitus with four or more veins reaching the hind margin. 



Derbini. 



b'^. Cubitus with less than four veins reaching the hind margin. 



c\ Cubitus simple or furcate, reaching the hind margin direct, not 



running into the first median sector Cenchreini. 



c^. Cubitus connected with the tirst median sector, forming an angular 

 or diamond-shaped cell; sometimes with a cross-vein near the 

 baae of the tirst median sector forming a triangular cell ; 



tegmina broad Ehotanini. 



a^. Clavus open, the cubital veins not reaching the hind margin but meetino- 

 the extended claval vein which extends to the last apical cell. 



Otiocerini. 



DERBINI. 



d^. Six or more median sectors ; shoulder keels very large Zeugma. 



a^. Five or less median sectors ; shoulder keels absent or very small. 



6\ Cubitus with four veins reaching the hind margin, the second vein 

 bifurcate ; the female genital styles generally small or very small. 



Mysidia. 



b'^. Cubitus with six or more veins reaching tbe hind margin, the second 

 vein not furcate ; female genital styles well developed . .Derbe. 



Deebe Fabr. 

 Derbe ivestwoodi Fowl. 

 BioL Centr.-Am., Ehynch. Homopt. i, p. 71 (1900) (part., wee figs.). 



