SYNGCA. 47. 
The walls of the nests made by insects of this genus are 
very thin and fragile, not unlike those of the structure built 
by Polybia sedula. In one nest the cover is remarkably 
elegant, being shaped like the half of a melon cut longi- 
tudinally, and moulded into ribs which run transversely 
across the nest, and have a gentle and regular curve. These 
ribs project about a quarter of an inch, and are nearly half 
an inch wide, and are as round and regular as if they were 
produced by cords wound upon the combs. 
The insect which made this nest is of a deep steel-blue 
colour, looking nearly black in a dim light. The head is 
rather large, and the abdomen is rounded and small, 
being connected with the thorax by a footstalk of moderate 
length. 
The two remarkable nests, which are figured in the 
illustrations on pages 48 and 50, come from different 
parts of the world, but they are similar in many respects. 
The long, flask-like nest was brought from Mexico, by 
Owen Rees, Esq., in 1834. ven before it was opened, 
its structure was evidently full of interest. The colour 
is dull white, not unlike parchment, and the texture of 
the materials is nearly as hard, stiff, and close as that sub- 
stance. When placed under the microscope, it is seen to 
be composed of a vast number of shining threads, crossing 
and recrossing each other in every direction, and pro- 
ducing a material like very thin, but stiff felt. 
It was suspended to a branch, but could not swing in 
the wind, because a twig descended into the neck and 
prevented any lateral motion. At the bottom of the nest 
there is a small and nearly circular aperture, through 
which the insects are enabled to make their exit and 
entrance, The length of the nest is about eight inches. 
So much for the exterior. On opening the nest, however, 
