2G0 Introducllon to the Si^noj^sis of (lie Aci-ididce. 



The ma^ostermim is the broad piece of the under tide that lies between 

 the middle legs, and is marked with one or more indentures. It 

 varies slightly in form, and may be used in describing species, though 

 I believe tliis has not been done, except in a few instances in Fischer's 

 Orthoptera Euro'pea. The pieces in front of the middle legs, extending 

 obliquely up the sides, are the episterna of the mesothorax ; the pieces 

 situated externally to and adjoining the insertion of the middle legs, 

 are the epimera of the mesothorax. 



The metastermnn is the under surface of the metathorax. and is sit 

 uated between the bases of the hind legs, and is usually marked with 

 a single or double indenture in the middle. The episterna and ephnera 

 of the metathorax correspond very nearly in relative position with 

 those of the mesothorax. 



These thoracic rings on their internal face furnish support for the 

 strong muscles necessary for the vai'ious movements of the wings and 

 legs ; and if we strip them of their appendages, and cut off the pos- 

 terior projection of the pronotiyin, limiting it to the length of the pro- 

 thorax, we will at once see that they are true homologues of the ab- 

 dominal segments, changed from the typical form only so far as is 

 necessary for the support and operation of the organs of locomotion. 



The legs, as in other insects, are divided into several parts or joints, 

 as follows : the coxa is the basal joint, by which the leg is connected to 

 tlie bodv; it is short in J.cridi(i«', but is usually enlarged. The iroc/i- 

 .anter, which is the next joint, is small, and can be best seen in the 

 anterior pair of legs. The third piece or joint is the thigh {femur'), 

 and is the largest portion of the leg. The fourth piece is the tibia or 

 shank, and is attached to the tip of the femur. The terminal portion, 

 which rests upon the ground, is the tarsus or foot, and is composed of 

 three joints ; the first, or basal, and the third (or terminal) joints, 

 being longer than the second (or middle) joint. The first has two 

 transverse indentures on the under side, which give it the appearance, 

 when seen on this side, of being three pieces, thus making the tarsus 

 appear five-jointed ; but seen from above, this shows but one, and the 

 entire tarsus but three joints. The third, or terminal' joint, is fur-, 

 nished at the tip with two claws (ungues), between wdiich in all the 

 groups, except Tettigini, there is a circular piece or pad (pulvillm). 



The posterior legs are much longer and stouter than the anterior or 

 middle pair, in order to fit these insects for leaping. The thighs or 

 femora are swollen or iucrassated near the base, to accommodate the 

 muscles necessary for this purpose. The external face, v,'hich is some- 

 times called the dish, is marked by numerous, alternate, minute ridges 

 and furrows, running obliquely in^vard and forward from each margin 



