2 — 



There are altogether 21 species enumerated as determined (1), of which 

 7 are described as new. There are also a number of nymphs of various 

 species of Gerridae, but I feel that at present my knowledge is not 

 sufficient to discriminate them ali clearly. The types of the new species 

 are ali in the collections of the Museum, and duplicates of raost of the 

 species enumerated are in the collections of Dr. Montandoli & myself. 







Darien 





Paraguay 





Ecuador 



& 

 Venezuela 



Bolivia 



& 

 Argentina 



Hydrometra argentina Berg 







— 



Gerris hyalinus Fabr. 



— 









flavolineatus Champ. 



— 









Perseus Kirk. * 







— 



— 



Andromeda Kirk. * 







— 



-— 



Potamobates bidentatus Champ. 



— 









Brachymetra Kleopatra Kirk. * 



— 









Paravelia inveruglas Kirk. * 



— 









Rhagovelia angustipes Uhi. 





— 







femoralis Champ. 





— 







Festae Kirk. * 



__ 









Corixa Rollarti Fieb. 



— 





— 





Griffinii Kirk * 



— 









pygmaea Fieb. 





— 







forciceps Spin. 







— 



— 



denseconscripta Bredd. 









— 



Pie a maculo sa Berg 







— 





Borellii Kiik » 







— 





Marfarega membranacea F. B. White 



— 









Anìsops elegans Fieb. 



— 



— 



— 





Antigone Kirk. 



— 





- 





Nolonecta bi fascia la Guér. 







— 



— 



Total 



11 



4 



9 



6 



(1) Hydrometra argentina Berg, has been recorded by Montandoli (1895. 

 Ball. Mus. Torino, voi. X, n. 219, p. 8) as having formed part of Dr. Borelli's 

 captures in the Argentine (Resistencia) but it was not included in the insects 

 1 bave examined. 



235 - Tip. Pietro G-erbone - Torino. 



