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Psyche 
[Vol. 89 
Grigiotermes metoecus (Fig. 4 i,j): These medium-sized domed 
mounds are often occupied by other species of termites and ants. 
The galleries are distinguished by smooth, shiny soil-colored floors 
and by small pieces of stone incorporated into the ‘ceilings.’ Indi- 
vidual deposits of fecal material used in construction are visible on 
the mound surface. 
Procornitermes araujoi (Fig. 4 k,l): These medium-sized, rounded 
mounds are often characterized by a thin layer of loose soil covering 
the outer shell. These mounds are quite brittle and homogenous and 
have galleries with a mottled lining of black soil and colored parti- 
cles, probably of fecal origin. They rarely extend below ground. 
Armitermes euamignathus (Fig. 5 m,n): This species builds very 
characteristic slightly domed mounds. The walls are very hard but 
the mound itself is only loosely held to the substratum with a cavity 
frequently occurring between it and the soil. The internal structure 
consists of large irregular chambers connected by very small galler- 
ies. During the alate flight season mounds of this species are charac- 
terized by earthen turrets several centimeters high built on the outer 
surface and serving as ‘launching platforms’ for alates. 
Cortaritermes silvestri (Fig. 5 o,p): This species builds soft, low 
rounded mounds with large irregular galleries. The mounds are fre- 
quently built around grass tussocks and extend several centimeters 
underground as in Velocitermes. 
Orthognathotermes gibberorum (Fig. 5 q,r): The low mounds 
built by this species are covered with loose soil and bound together 
by living grass stems. The galleries are regular and homogenous 
throughout. The mound frequently extends several centimeters 
underground but can be separated easily from surrounding soil 
when pried up. 
B. Mound hardness and nest material 
The ‘hardness’ of a mound was measured using a soil penetrome- 
ter which measures the force necessary to push a metal cone into the 
soil. The resistance to penetration is obtained by dividing the load of 
penetration (force applied) by the area at the base of the cone, which 
was 637.939 mm 3 . The resistance to penetration was taken as a 
measure of hardness of the mound surface. 
A termite mound is not a solid structure but consists of a complex 
system of galleries and chambers. The outer wall is often thick 
enough for penetration of the whole cone. However, at times, the 
