124 
Psyche 
[March 
Relatively coarse and irregular chips of punky wood form the 
basic construction material for the nests. The particles, varying from 
grey to brown or black and resembling sawdust when dry, are 
securely bound up in a silken matrix. The entire nest interior, in- 
cluding the cells, is also coated with a silk-like material. Little or 
no unincorporated nest material remains in the bottom of the nest. 
In general construction, the nest of M. thripoctenus bears a re- 
semblance to that of M. guianae which is also made of rotted wood 
pellets and has a straight, non-spiraled pedicel (see photo in Howes, 
1925, p. 276). The nest of another undescribed species from 
Ecuador is also similar in appearance. 
Because the two nests were suspended from different plants, it 
appears that M. thripoctenus does not exhibit the host plant specificity 
so characteristic of M. comes. Neither, as one might suspect from 
this, does M. thripoctenus appear to derive its nest material from the 
host leaf in the manner of M. comes; the leaf undersurface bears 
no evidence of a scraped area in the vicinity of the nest attachment. 
And although the nests of both species are coated with a silk-like 
material, M. thripoctenus females have only sparsely scattered hairs 
on the apical tergite where M. comes exhibits its well developed 
setal brush. 
Cell Contents. Upon dissection, each nest was found to contain 
six pocket-like cells, each corresponding to one of the pouch-like 
lobes (with the extra cell in the center). As with M. comes , the 
cells were mass provisioned, and no two cells were at the same 
stage of development. Three cells of the Andrews nest contained 
pupae: one fully pigmented female, one male with cinnamon eyes, 
and one completely white female. All were oriented with head in 
the bottom, anus at the cell opening. The remaining three cells of 
the nest contained a prepupa, a small larva with 1 7 1 thrips, and 
an incompletely provisioned cell containing 58 thrips with no evi- 
dence of egg or larva. The Janzen nest, which was less complete, 
contained one newly emerged adult with freshly expanded wings 
and, in another cell, a pupal female. A third cell contained a 
shriveled egg or young larva with 70 thrips. Of the remaining cells, 
one contained a dozen thrips and two were empty. 
The Andrews nest was collected at night when all adults were 
presumed to be present. It yielded three females and one male. 
The other nest, collected during the day, contained no adults except 
for the newly emerged female still in her cell. In the absence of 
further data, the social status of M. thripoctenus must remain un- 
