96 CALIFORNIA ACADEMY OF SCIENCES. 



been carted to the place two years before and covered 

 a deposit of grass and leaves. As the leaves and grass 

 decayed, a narrow space or crevice was formed, and in 

 this was found numerous collections of clay pellets that 

 appeared like the excrement of mice. The tunnels were 

 plentiful, some above and some below this crevice, but 

 many had an outlet into this fissure and some ended 

 therein. A number of these larvae or grubs were removed 

 from their habitat and placed in a box with earth and 

 roots from a garden; the box let into the ijround, and 

 though all care and attention was given them and though 

 many were large and robust the new conditions did not 

 suit them. Some continued living for a whole year but they 

 all finally died, not one reaching the perfect state. Dur- 

 ing examination pellets were found in the box and this 

 fact explained the nature of them; they were noticed to 

 be of a different color, which suggested another fact — 

 that their food had been improper. The next experiment 

 was made with the clay and materials found in their hab- 

 itat and they passed their metamorphoses in regular 

 order. It appears that this insect when in the grub state 

 requires clay as part of its diet. 



14 pellets, (fig. VIII), air dr}-, weighed 0-354 grams 



Weight after being burnt 0.230 '-' 



Loss by ignition 0.115 " 



What nutriment this insect can extract from clay can 

 only be conjectured, as the qualificative admixtures are 

 unknown; the mycelium of fungi may constitute a portion 

 of the material for tissue building; but as this is also 

 doubtful the explanation is not forthcoming. If the pro- 

 portion of refuse be taken as a criterion the earthy mat- 

 ter is exactlv two-thirds of the whole food. 



