26 THE SKIN OF INSECTS. 



into the fore breast-plate, the mid breast-plate, and the 

 hind breast-plate ('). 



On the inside of the breast-plate, in the interior of 

 the breast, is another singular piece, usually jointed 

 with the hinder and inner end of the breast-plate. It 

 varies much in form, but frequently resembles a Y, 

 and is hence called the prop, or Y piece, by the 

 French naturalists ( 2 ). This is always present in each 

 of the three rings, and, like the breast-plate, may be 

 considered as the fore breast-prop, the mid breast- 

 prop, and the hind breast-prop ( 3 ). It extends in some 

 cases within the head, and in others, as in the tree- 

 hoppers, within the abdomen, and was then termed 

 by Reaumur the scaly triangle. 



The chief use of the breast-prop, seems to be to 

 afford an attachment and lever to the muscles which 

 move the fore legs; very evident in the singular 

 breast-prop of the mole cricket : and, according to 

 Audouin and Marcel de Serres, to protect the nerves, 

 by separating them from the gullet, stomach, and 

 heart. The hind breast-prop has often attracted atten- 

 tion from its singular trident-like form. 



The fore corselet, under side ; a, b, the breast-plate ; c, c, the 

 under flanks. 



1) In Latin Prosternum, Mesosternum, 



(2) In Latin Furca, or Entothorax. 

 (3) In Latin Antefurcu, Prof urea, and Postfurca. 



