230 
Psyche 
[December 
Dr. E. S. Ross writes that these specimens were collected in the day- 
time during a search for Embioptera, probably “under stones on 
sandy silt”. “The locality was extreme desert typical of coastal Peru. 
It must have shown some effects of coastal fog, such as lichens on 
rocks, else we wouldn’t have stopped for embiids” (E. S. Ross, in 
litt.). Dr. E. I. Schlinger recalls this as a “loma zone surrounded 
by arid to semi-arid vegetation”. He collected spiders under rocks 
and believes the wasps may have been collected there, too. Since these 
females have all the features of hypogaeic Hymenoptera, their oc- 
curence under rocks seems logical enough. 
Ross and Schlinger collected many male Plumarius in Peru 
(though none at this locality) and Dr. Marius Wasbauer has been 
studying these in a preliminary way. He writes that there appear 
to be three species in Peru and Ecuador. Since Plumarius is com- 
pletely unworked taxonomically, I shall refrain from placing a 
specific name on the females. The specimens have been returned to 
the California Academy of Sciences, where they await inclusion in 
a much-needed revision of this genus (hundreds of males have now 
accumulated in museums). 
I shall present first a detailed description of these females, then 
a few notes on male structure, and finally a discussion of the prob- 
able relationships of the Plumariidae. Since both females are some- 
what imperfect, my description is a composite from the two 
specimens, parts of one of which have been mounted on a slide. The 
two specimens are virtually identical in size and structure. 
Description of the female Plumarius. — Length about 5 mm ; body 
somewhat depressed, wings and tegulae completely absent (Fig. i); 
body light castaneous, shining, the appendages testaceous. Head 
strongly depressed, very thin, prognathous; eyes of moderate size, 
not protruding from surface of head, each containing approximately 
150 facets; ocelli absent (Fig. 2). Occipital Carina closely surround- 
ing foramen, complete but not at all visible in frontal view; under 
surface of head with mouth-parts far removed from occipital fora- 
men, the space filled by a broad genal bridge, the midline narrowly 
depressed but not really sulcate; hypostomal sulcus closely paralleling 
the margin of the broad proboscidial fossa. Labium simple, palpi 
with three subequal segments (Fig. 6) ; maxillae small, closely as- 
sociated with labium, bearing fairly long, 5-segmented palpi 
(Fig. 7) ; mandibles large, strongly tapered toward the apex, bear- 
ing three large apical teeth, each of them (but especially the large 
apical tooth) marked by a thick, horny plate; mandibles with many 
small sensilla and with numerous setae arising near the base (Fig. 
