586 EXTERNAL ANATOMY OF INSECTS. 



many muscles, and run in various directions both on the 

 interior of the crust and of the metaphragm. These little 

 seams are not to be found so generally in the other Or- 

 ders ; but very frequently, as has been before observed, 

 where there is an exterior impression of the crust, or a 

 suture, one of these forms its internal base. 



ii. Processes of the pectus*. We are next to consider 

 the internal processes of the breast of insects: these con- 

 sist for the most part of the endostemum, or internal 

 sternum, and its branches. As the principal feature of 

 this are the processes which rising from it serve as points 

 of attachment to the muscles that move the legs, &c, I 

 shall confine myself to them — they are, the atitefurca, the 

 medifurca, and the postfurca. 



1. Antefurca h . The first portion of the endosternum, 

 or the internal prosternum, branches into the antefurca. 

 In the Coleoptera a plate varying in shape and direction 

 sends forth a pair of mostly vertical processes of a car- 

 tilaginous substance d , differing in height in different 

 genera. In Carabus L. there is neither this plate nor its 

 processes ; but in Dytiscus the latter are very visible. A 

 very singular and complex machine represents the part 

 we are considering in that extraordinary insect the mole- 

 cricket ( Gryllotalpa Latr.). When we look at its prodigi- 

 ous arms and consider their office e , we may imagine that 

 the requisite apparatus for moving them must be very 

 powerful and peculiar. Their Creator has according- 

 ly provided them with a machine for this purpose more 

 than usually complex, extending from the prothorax to the 



a Plate XXII. Fig. 5—7. b Ibid. Fig. 7. c Ibid. a. 



d Ibid. e. e See above, Vol I. p. 191. and II. p. 257, 366. 



