LYRNESSUS.—LEPTOCORISA. 161 
Division LEPTOCORISARIA, 
Gerrida, Stal, Ofv. Vet.-Ak. Férh. 1867, p. 543. 
Gerrina, Stal, En. Hem. i. p. 217 (1870). 
Leptocorisaria, Stal, En. Hem. iii. p. 85 (18738). 
This small division, as represented in America, is almost confined to the Neotropical 
Region. Two genera are known, both of which are represented in Central America. 
The second joint of the rostrum is not longer than the two apical joints taken 
together. 
LYRNESSUS. 
Lyrnessus, Stal, Rio Hem. ii. p. 59 (1862) ; Ofv. Vet.-Ak. Forh. 1867, p. 543; En. Hem. iii. p. 86 
(1873). 
Coristenia, Costa, Rendic. Accad. Napol. ii. p. 260 (1863). 
But one species of this genus has been recorded; and I have had no opportunity as 
yet of examining it. 
1. Lyrnessus geniculatus. 
Leptocorisa geniculata, Guér. in Sagra’s Hist. de Cuba, Ins. p. 392°. 
Paryphes tibialis, Stal, Rio Hem. i. p. 31. 2”. 
Coristenia flavicosta, Costa, Rendic. Accad. Napol. ii. p. 261. 
Lyrnessus geniculatus, Stal, En. Hem. i. p. 217. 1°. 
Hab. Mexico, Oaxaca ®?.—Cusa!?; Brazit, Rio Janeiro 2%. 
LEPTOCORISA. 
Gerris (p.), Fabr. Ent. Syst. iv. p. 187 (1794) ; Syst. Rhynch. p. 160 (1803). 
Myodocha, Latr. Gen. Ins. iii. p. 126 (1807). 
Leptocorisa, Latr. Régn. An. v. p. 197 (1829) ; Stal, En. Hem. iii. p. 86 (1873) ; Dall. List Hem. 
ii. p. 481 (1852). 
Myodochus, Ol. Enc. Méth. vii. p. 105 (1811) ; Burm. Handb. ii. 1, p. 825 (1835). 
Stenocoris, H.-S. Wanz. Ins. ix. pp. 244 & 275 (1851). 
Rhabdocoris, Kol. Mel. ii. p. 67 (1845). 
Gerris, Stal, Hem. Afr. ii. p. 87 (1865) ; Ofv. Vet.-Ak. Forh. 1867, p. 543. 
The elongated head, with the lateral lobes much longer and meeting in front of the 
central lobe, will distinguish Leptocorisa from Lyrnessus. It is found both in the 
Nearctic and Neotropical regions, and is represented in all the great divisions of the 
world. 
1. Leptocorisa filiformis. 
Cimex filiformis, Fabr. Syst. Ent. p. 727.157; Goeze, Ent. Beytr. ii. p. 251.5; Fabr. Spec. Ins. ii. 
p. 375. 225; Mant. Ins. ii. p. 308. 293; Gmel. Syst. Nat. i. 4, p. 2191. 525. 
BIOL. CENT.-AMER., Rhynch., August 1881. 21 
