300 
A New Gregarine 
swollen laterally to form four blind pouches or diverticula; each of these 
pouches being further partially divided into two. The wall of these pouches 
shows a number of irregular swellings visible on the surface. The epithelial 
cells of this region are of two kinds: (1) large cells, somewhat rounded in shape, 
which contain a number of coarse inclusions, and (2) typical epithelial cells. 
These inclusions of the large cells were thought by Karawaiew (1899) to 
be flagellate organisms, but later it was shown by Escherich (1900) that they 
are yeast cells: these live in the epithelial cells as symbionts and apparently 
play an important part in the digestive processes o{ the larva. In between 
the yeast infected cells there occur a number of typical epithelial cells, which 
possess an inner striated margin, absent in the case of the former. 
The epithelium of the diverticula was found to be almost free from the 
gregarine, which seems unable to lodge in the yeast-infected cells. A certain 
proportion, however, of the simple epithelial cells lying between these had 
gregarines attached to them (Fig. 2). 
Fig. 2. Section through part of one of the lateral pouches showing the two types of cell. A, 
typical epithelial cell infected by a gregarine. B, large cell containing the symbiotic yeasts, 
x 667. 
The second division of the mesenteron is wide, and it passes by a sharp 
constriction on the ventral side into the U-shaped much narrower hind-most 
division. Both these regions of the midgut are lined exclusively by a typical 
epithelium, and both were very heavily infected with the gregarine. 
At the junction of the mesenteron with the hindgut there are six malpighian 
tubules. The hindgut is a long coiled tube consisting of four divisions. 
The midgut of the imago is much shorter than that of the larva. At its 
anterior end there are similar lateral pouches, but they are relatively smaller 
in size, and the cells which contain the symbionts are differently shaped from 
the corresponding cells in the larva. 
