2 Cameron, Hymenoptera from Chili. 



described a genus Nomadina from the Amazons, which 

 he correctly regarded as nearly related to Trigonalys, and 

 which is undoubtedly closely allied to the present genus. 

 Both have a considerable likeness to a bee, as is indicated 

 by the Westwood's choice of a name from the bee genus 

 Nomada. The two genera may be separated as follows : — 



Wings with four cubital cellules ; the third cubital cellule 

 small, receiving the second recurrent nervure; the 

 first joint of the antennae small. Nomadina. 



Wings with three cubital cellules ; the third cubital 

 cellule large, extending to the apex ; the second 

 cellule receiving the recurrent nervure. Liaba. 



These two genera then will be included in the family 

 Trigonalidce, which will now be divided into two tribes, 

 the differences between them being best exhibited in 

 synoptical form. 



Antennae at least 21-jointed; head largely developed 

 behind the eyes ; wings with three transverse cubital 

 nervures ; the first recurrent nervure received in the 

 second cubital cellule, which is much narrowed, if 

 not petiolate, above ; the second abdominal segment 

 larger than any of the others. TrigonalidcB . 



Antennae i6-jointed; head not much developed behind 

 the eyes ; wings with two or three transverse cubital 

 nervures ; the first transverse cubital nervure received 

 in the first cubital cellule ; the second cubital cellule 

 not much narrowed above ; the abdominal segments 

 not differing much in length. Nomadincz. 



Trigonalys has a wide distribution over the globe, but 

 the species are few in number and, so far as I know, are 

 rare in collections. In North America a few species are 

 known. I have myself described six species from Central 

 America, and species have also been recorded from South 

 America. In Britain we have one species, T. anglicana 

 Shuck. 



