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haematoxylin, alcohol-hardened specimens are seen to 
contain numerous stained granules, collected especially 
in the outer portion of the cell. These are especially 
abundant in the anterior portion of the mid-gut. 
They have also, very frequently, a number of small 
clear vacuoles (droplets), which become more frequent 
and of larger size towards the free border of the cell. 
The most marked feature of the cell is the clear striated 
border which is present in all the cells of the mid-gut, 
but absent in all other portions of the alimentary canal. 
The striated border is best marked in the undistended 
organ, and becomes almost invisible in the fully 
distended state, when the cells are much flattened. 
The nucleus of these cells is large and centrally 
situated. 
The muscular coat is very thin. It consists of 
an open mesh-work of long muscular fibres running 
longitudinally and circularly. 
The individual muscle fibres are very long, 
fusiform, striated fibres. On the outer surface of the 
mid-gut lie numerous large branched cells in which 
the small tracheae end, and from which bundles of 
minute structureless air tubes pass into the wall of the 
mid-gut. These cells are frequently well shown in 
gold chloride specimens. Similar cells occur through¬ 
out the viscera in connexion with the tracheal endings. 
The Hind-gut .—Structurally the small and large 
intestine are similar, whilst the dilatation beyond the 
pylorus, and especially the rectum, differ from these. 
The dilatation which occurs at the origin of the 
malpighian tubules is thin-walled and poorly supplied 
with muscle fibres. The cells lining it are small and 
flattened. 
The intestine is lined with a single layer of large 
cubical cells ; external to these is a muscular coat. 
