This usually extends into the abdomen, and is a 
prominent object in dissections and sections (Fig. 
38). 
The Homologue of the Proventricuius. —There is no 
true proventriculus as in many insects. There is, 
however, an interesting fold of the fore-gut into the 
mid-gut which represents this organ. The muscular 
bundles are here increased, and the whole forms a 
valvular muscular organ (Fig. 38). 
The Mechanism of Feeding. —The powerful pump¬ 
ing action which must result from a drawing asunder 
of the three large chitinous plates of the pumping 
organ is very evident. These plates, also, when drawn 
apart must, by reason of their spring-like shape, revert 
to their original positions close together, without any 
muscular aid. Posteriorly the valve-like arrangement 
mentioned before prevents regurgitation. Further, 
when the blood reaches the junction of the oesophagus 
and mid-gut the invaginated portion is withdrawn, and 
is distended by the entering blood into a distinct 
c crop,’ the valvular function is suspended, and the 
blood flows onward. 
The Mid-gut. —The mid-gut extends from the 
proventriculus to the origin of the malpighian tubes. 
The anterior narrow portion of the mid-gut lies 
in the thorax, and does not become distended with 
blood. The posterior portion when fully dilated fills 
the greater portion of the abdomen, the viscera being 
pushed into the last few segments. 
The Hind-gut. —The hind-gut is short and passes 
in one or two bends from the pylorus to the anus. 
Immediately beyond the pylorus there is a considerable 
dilatation which is poorly supplied with muscular fibres: 
into this open the five malpighian tubules. For a short 
distance beyond this the lumen is narrow (ileum), but 
