56 
Psyche 
[March 
Pseudocharter gus fuscatus has been recorded only from the Amazon 
basin. Its nest is remarkable in that it is enclosed in a transparent 
envelope. This feature is shared with the congener P. charter goides. 
P. fuscatus also has cells that open upward, an extremely rare trait 
in the Vespidae. The nest of Stelopolybia testacea, a species that 
ranges from northern South America to Bolivia, is very similar in 
structure to those of 5 . pallipes and S. cajennensis. The nest described 
here was unique, however, in having been constructed in a relatively 
exposed site, on the underside of a palm spathe. Moreover, it was 
one of the largest and most populous nests of any social vespid 
ever taken in the American equatorial tropics. 
A sample of the adult population of each nest has been deposited 
in the collection of the Museum of Comparative Zoology at Harvard 
University. The field numbers are 71 and 265 for the colonies 
of P. fuscatus and S. testacea , respectively. One specimen of the 
parasite of 5 . testacea has also been placed in the MCZ collection. 
Pseudocharter gus fuscatus 
I found a single colony on November 30, 1967, in the Utinga 
district on the outskirts of Belem, Para, Brazil (i°27'S, 48°29'W). 
The nest was located in an isolated tree growing in marshy soil at 
the upper end of an arm of a reservoir. The trunk of the tree would 
stand in shallow water during the rainy season (January through 
June), when the reservoir is full. The tree was about eight meters 
tall and twenty meters distant from tall second-growth forest, which 
surrounded it on three sides. The nest was built in the thick foliage 
at the end of a small branch about four meters from the ground. 
The adult wasps were very timid, and the slight shaking of the 
nest as I collected it caused them all to retreat inside. Even more 
violent shaking after the branch was clipped would not bring them 
out to defend their brood. Only when the colony was placed inside 
Fig. 2. Nest of Pseudochartergus fuscatus. The combs are visible through 
the entrance. The parallel ridges in the broad sheet of transparent film 
to the right of the combs probably mark boundaries between successive 
additions of the secretion. Slightly larger than natural size. 
Fig. 3. Upper comb of Pseudochartergus fuscatus nest, showing brood 
distribution. The two dark cells just above the five pupae near the center 
contain eggs of the third generation of brood. Large larvae are visible in 
surrounding cells. Some of the cells among the outer pupae are empty but 
still have fragments of cocoon attached to them; these are cells from which 
adults emerged after the nest was collected. 1 1/2 times natural size. 
