154 HYMENOPTERA. 



genus Nectar ina is a short plump wasp, somewhat like Odyne- 

 rus in shape ; its distinguishing mark is the concealment of 

 the postscutellum by the scutellum. Nectarina mellifica Say, 

 of Mexico, builds a large nest externally like that of a wasp, 

 but it is more irregular, and the papery covering consists of 

 but one layer. The interior of the nest is very different, the 

 galleries of cells, instead of being parallel, being arranged in 

 concentric spheres. 



Chartergus has the tip of the clypeus slighted excavated, and 

 an oval sessile abdomen. C. chartarius Olivier makes an ex- 

 ceedingly thick tough nest, attached by a broad base to the 

 bough of a tree, about twice as long as thick, and ending in a 

 cone, pierced in the centre by the entrance which passes 

 through the middle to the basal gallery ; the other galleries are 

 formed by a continuation of the sides of the nest, and arrayed 

 in a conical plane. 



In Tatua, the abdomen is pedicelled, but the petiole is not 

 enlarged, and the abdomen itself is very regularly conical. T. 

 morio Cuvier, from Cayenne, forms a nest like that of Charter- 

 gus ; but the galleries form a flat floor, and each gallery has an 

 entrance from the outside of the nest, where in the latter there is 

 one common entrance. Plate 5, Fig. 9, shows how the bases 

 of the cells are laid out on the edge of a gallery. In Synceca 

 the peculiarly shaped abdomen is cordate and compressed. The 

 curious nest of S. cyanea Fabr. is formed of a single layer of 

 cells fixed against the trunk of a tree, and covered in with a 

 dense covering made from the bark of dead trees. Some nests 

 of Synoeca are three feet long. In the very extensive genus 

 Polybia, which resembles Polistes in its general shape, the abdo- 

 men is pedicelled, and the mandibles are four-toothed. The nests 

 are somewhat like those of Chartergus, but much smaller. Sev- 

 eral species occur in Mexico, and in Brazil the number of 

 species is very great. In Apo'ica the abdomen is very long, 

 and the third segment is as long as the second. Plate 5, Fig. 

 11, represents the nest of Apoica pallida Olivier, from Cayenne. 

 It is unprotected, with a conical base, and with a single row 

 of cells. 



In Icaria we have an approach to Polistes in the slender 

 series of cells composing the nest, forming two or three rows 



