CALCIUM CARBONATE IN DIPTEROUS LARVAE 619 
in the body of the larva, but passes from the Malpighian tubes 
into the hind-gut, whence it is expelled from the body just 
before the larva begins to pupate. He admits, however, that 
he never actually saw the process of expulsion of this product 
TEXT-FIG. 5. 
Calcospherites of Acidia heraclei, ato e. a, a calcospherite 
examined by polarized light, showing the black cross; 6 and ¢, 
double calcospherites ; d, very small simple, double or multiple 
calcospherites ; ¢, caleospherite in diluted acetic acid showing 
collapsing stroma ; /, intracellular calcospherite of Agromyza 
larva. 
of excretion. In several cases he found the calcareous sub- 
stance retained in the pupae of Ptychoptera. 
Henneguy (8, 1897) found that the calcospherites of A gro- 
myza larvae persist in the pupae, but he did not find them 
in the adult flies. He considered that the existence of calco- 
spherites was not general, and was very probably abnormal, 
