On the calcium carbonate and the calcospherites 
in the Malpighian tubes and the fat body of 
Dipterous larvae and the ecdysial elimination 
of these products of excretion. 
By 
D. Keilin, Se.D., 
Beit Memorial Research Fellow. 
(From the Quick Laboratory, University of Cambridge. ) 
With 5 Text-figures. 
CONTENTS. 
PAGE 
1. THE PRESENCE OF CALCIUM CARBONATE IN THE MALPIGHIAN 
TUBES 5 ‘ ; 4 : 3. (sll 
2. CALCOSPHERITES IN THE ne ‘Bone 2 . ‘ : 5 ale! 
3. CALCOSPHERITES IN THE MALPIGHIAN TUBES . ; 617 
4. Ecpystat ELIMInation oF Catctum CARBONATE DURING Mara. 
MORPHOSIS : 617 
5. HYPOTHESES AS TO THE ee AND TGNGrON OF ievrias 
CARBONATE IN THE LARVAL Bopy . : : ; S624 
6. CoNcLUSIONS ; : : : f : , 4 7) 623 
7. REFERENCES ; Z E : F 5 : : Ged 
1. THe PRESENCE or CaLcIUM CARBONATE IN THE 
MALPIGHIAN TUBES. 
Lyoner (11, 1832) was the first to notice in the larva of 
Ptychoptera two milky-white vessels running throughout 
the length of the body. Similar vessels have been discovered 
in the larva of Eristalis by Batelli (1, 1879), who has 
rightly described them as saceate dilatations of the anterior 
pair of Malpighian tubes filled with calcium carbonate. Quite 
