Undescribed anatomical features of the gut of the house cricket, Acheta domesticus L. (Insecta, Orthoptera)

Summary

The following new anatomical features of the gut of Acheta domesticus are described and discussed:

	1.A thin-walled dorsal evagination of the oesophagus, which may serve to circulate digestive fluid in the crop.
	2.Lateral invaginations of the wall of the posterior oesophagus and anterior crop, separated from the circular muscle layer and allowing considerable enlargement of the foregut during feeding.
	3.Strands of muscle and connective tissue linking the caeca and crop to the thoracic cuticle, innervated in part from the prothoracic ganglion, which may serve to register the extent of gut filling.
	4.Evidence from the arrangement of the gut tracheae and nerves of rotation of parts of the gut from their original ancestral position, the gizzard and caeca being rotated through 90° and the crop through 180°. It is suggested that these rotations have been necessary to accommodate the gut components to changes in the shape and proportions of the body during the evolution of the cricket lineage.