of Exotic Hymenoptera. 83 



Genus Liogastea, Perty. 

 1. Liogastra quadriplagiaia. 



L. nigerrima, pilosiusciila ; abdominis basi plagis quatuor lutescenti-albis 

 ornata; capite supra, thorace antice et lateraliter albo-pilosis ; alis 

 nigrescentibus violaceo-micantibus. 



Male. Length 9| lines. Jet-black, and thinly sprinkled with pale 

 glittering silky pubescence ; the face as high as the insertion of the 

 antenna?, and a line on each side above them, nearly meeting in front 

 of the ocelli, covered with white pubescence ; the clypeus widely emar- 

 ginate ; the anterior margin of the labrum rounded ; the antennae rufo- 

 piceous beneath, and with an elevated carina between their insertion. 

 Thorax : two transverse spots in front, a larger subovate one beneath 

 the wings, and a line on each side of the metathorax covered with 

 white pubescence ; the scutellum bituberculate ; the wings nigro- 

 fuscous, with a bright violet iridescence. Abdomen : a large ovate 

 macida of white pubescence on each side of the two basal segments. 



Female. This sex differs in having the face black, and the white spots 

 on the thorax nearly obsolete : the spots on the abdomen are much 

 smaller, and the apical segment is pointed ; in the male it is bilobed. 



Hub. Mexico. 



This species was taken by M. Salle ; it is one of the most beautiful 

 of the whole family of Apidae, and is the fourth species discovered of 

 the genus to which it belongs ; the other three are from Brazil. 



ICHNEUMONLTLE. 



Family Aulacidae, Shuck. 



Genus Trigonalys, Westiu. 



1. Trigonalys ornata. 



T. nigro-fusca ; capite thoraceque maculis flavis ornatis ; abdomine flavo- 



fasciato ; alis hyalinis ; pedibus flavis. 



Length 5^ lines. The head large, wider than the thorax ; the mar- 

 gins rounded, somewhat flattened in front ; the clypeus transverse, 

 its anterior margin slightly rounded and emarginate in the middle ; the 

 head, mandibles, and four middle joints of the antenna? of a sulphur- 

 yellow ; the mandibles with three black teeth ; a minute black, or rather 

 a fuscous spot between the antenna?, a circular broad ring above them 

 extending to the first ocellus and uniting with a subtriangular spot 

 enclosing the posterior ocelli, on each side of which is another curved 

 fuscous stripe, which becomes narrower and unites at the margin of the 

 vertex. The thorax and legs are yellow ; the former has three broad 

 longitudinal stripes on the mesothorax, another on the scutellum and 

 metathorax in the middle, and also a small triangular spot on each 



82 



