1988] Carpenter & Wenzel — Mischocyttarus from Costa Rica 97 
on leaf veins, point cells roughly laterally (as opposed to vertically), 
build some cells much deeper than neighboring cells, and paste 
carton onto the silk caps of cocoons strongly domed beyond the end 
of the cells. 
Discussion 
Recognition of this new species, defined morphologically, should 
not be interpreted as support for the widespread and probably 
erroneous opinion that every species of paper wasp has a distinctive 
nest form of its own. However, the obvious differences between the 
nests described here demonstrate that closely related species may 
vary greatly in architecture. M. alienus and moralesi build a long, 
pale pedicel and continue mostly along the vertical axis. M.fraudu- 
lentus builds simultaneously several short pedicels and separate 
groups of cells that fuse mostly horizontally. M. pelor probably 
begins like fraudulentus but shows the peculiar back-to-back ar- 
rangement of cells in subsequent construction. 
It is rare to find pupae in polistine nests as small as those de- 
scribed for M. alienus, moralesi and fraudulentus. With several 
nests now examined, it seems that founding females of these species 
ordinarily provision few larvae simultaneously, and provision un- 
evenly, producing few pupae per comb. This would result in unusual- 
ly small colony size after worker emergence. To accommodate for 
this low productivity, perhaps females simultaneously maintain 
several nests separately, as is known for Polistes (Jeanne, 1979) and 
Ropalidia (ltd, 1986), or build and abandon several nests sequentially, 
as suggested for one Ropalidia species (Wenzel, 1987). Present in- 
formation is inadequate to determine if either of these possibilities 
occurs. Unlike these three species, the size of the M. pelor nest (and 
presumably the colony) is not unusual for Mischocyttarus. 
The architecture of the M. pelor nest is perhaps caused by contin- 
uous building in a confined place or by inversion of a small comb 
and subsequent disorientation of ordinary cues used by the builders. 
However, several facts support the opinion that this nest is not such 
a monstrosity. Most nests built in too small a cavity are soon 
abandoned or modified to fit the space available. If the nest was 
built on the rib of a leaf, it probably would not have been confined 
in such a way as to explain the architecture. In many genera, includ- 
ing Mischocyttarus, most nests which have been rotated or inverted 
during construction are not remodeled completely, but rather older 
