IX. 
A SPINNING DIPLOPOD. 
It has long been known that females of Polydesmus and lulus lay 
their eggs in large clusters and protect them with walls of earth and 
vegetable matter, probably hardened by some secretion of the animal. 
There have also been numerous reports of the fact that for protection 
during moulting somewhat similar structures are provided. The 
latter, at least, are probably constructed of matter which has passed 
through the digestive canal, while the material of the former seems 
from the observations of Vom Rath not to have been thus elaborated. 
That observer is, however, certainly in error in supposing that the 
moulting-nests are not of definite and constant shape in the same 
genus or family. Our smaller North American Polydesmidae con- 
struct flattened or lenticular nests with thin, almost papery, walls, 
while Oxydesmi observed in Liberia have large ovoid chambers en- 
closed by thick clay walls. As in both cases the external and inter- 
nal appearance of the nests is characteristic and constant, and as the 
wall is complete and apparently of the same structure throughout, 
we are obliged to infer either that the material for finally closing 
the entrance is supplied in the manner suggested, or that the animals 
provide themselves in advance with enough extra clay or vegetable 
debris to finish their cell. It is certain also that the matter voided 
after the creature has taken up residence in its chamber is added to 
the walls, so that it becomes antecedently probable that the whole 
structure is built in the same manner. 
With regard to the Coelocheta (Lysiopetaloidea and Chordeumatoi- 
dea) a different condition is known to exist. Fanzago has reported 
for Lysiopetalum, and Waga and Latzel for Craspedosoma, the exist- 
ence of nests composed of webs, but of the character of either the 
nests or the webs no account is current in the literature of the sub- 
ject, so that it was not without surprise that recently I found on top of 
Lookout Mountain, Tennessee, what appear to be young specimens 
of Cleidogona (Cryptotrichus Packard), in loose, white, silky cocoons 
built on moist decaying leaves. The cocoons were so transparent 
that the form and color of the inclosed animal was not entirely ob- 
scured ; indeed I opened the first one to see what sort of larva looked 
so much like a young Cleidogona ! The occupant of the second co- 
coon soon became restive when his establishment was exposed to 
Brandtia, p. 41. 
