1966] 
M uma — Solpugida 
255 
entrance (Fig. 4). This plug, by the mechanics of digging, was ex- 
tended as the burrow was deepened. 
Probing usually involved only the palpi; although occasionally the 
first legs were used. This activity was confined to the unexcavated 
burrow face. Probing was interpreted as a feeling for large particles 
but may have assisted in the removal of loosened soil particles. 
Tamping was confined to excavated and plowed soil. This activi- 
ty was interpreted as a reflexive packing of loose soil which assisted 
in the construction of the burrow plug (Figs. 3 and 4). 
When the burrow was completed, the solpugid was enclosed in a 
low- vaulted, oval to round space to which the term “nest” has been 
applied (Figs. 2 and 5). Vertical and horizontal nest location varied; 
this is probably governed by inherent factors, but could be an expres- 
sion of soil type and condition. Nests utilized for ecdysis, egg deposi- 
tion, and probably hibernation were in longer and deeper burrows 
than those utilized for daytime resting or digestion. 
Specific Burrowing Habits 
A systematic comparison uf the burrowing habits of Eremorhax 
magnus (Hancock), E. pulcher Muma, E. striatus (Putnam), Ere- 
mobates durangonus Roewer, E. nodularis Muma, E. palpisetulosus 
Fichter, Therobates bilobatus Muma, T. n. sp. ( arcus group) Am- 
motrcchula peninsulana (Banks), Ammotrechella stimpsoni (Put- 
nam) and Branchia brevis Muma, revealed variations, possibly sig- 
nificant at the species, genus, or family level. In the following sub- 
titled paragraphs, these variations are presented and discussed. 
Eremorhax magnus (Hancock). — Burrow depths of 1.3, 1.9, 
and 5.4 cm have been recorded for immatures. Immatures and fe- 
males were collected from nests beneath cow dung (i.e., cow pies) 
and rocks. A gravid female was dug out of a burrow 22.9 cm deep. 
Burrows were constructed at an abrupt angle to the soil surface, 45 0 
or more. 
This species burrowed extensively in laboratory terraria, com- 
pletely churning the soil in a single night. The usual biting, raking, 
and plowing were employed vigorously. Variation was noted in plow- 
ing. Chelicerae were slightly separated and held slightly above the 
base of the soil pile. Moist soil was frequently lifted and carried in 
the chelicerae, palpi, and first legs. The palpi were used consistently 
in probing. 
Eremorhax pulcher Muma. — This species was not observed in 
burrows under field conditions. 
In the laboratory, immatures utilized biting, raking, and plowing 
when burrowing but plowed much less frequently than E. magnus . 
