150 



OUR HOUSEHOLD INSECTS 



again, when closed, completely cover the rest of the 

 mouth organs ; on their removal, the secondary jaws, or 

 maxillae, come into view (Fig. 46) ; 

 these are very much like the cock- 

 roach's, the inner lobe (lacinia) 

 being tipped with two sharp teeth, 

 and received for protection's sake 

 into a groove of the outer (galea), 

 and they are furnished with a pair 

 of five-jointed palpi. Beneath, or 

 rather behind them, is the labium, 

 showing again a similar structure 

 to that of the prototype, and equally 

 obviously composed of a pair of jaws 

 which have coalesced, i.e., have become united into a 

 single organ in their basal portion ; this, too, carries a 



FIG. 45. Mandible of 

 Cricket. 



FIG. 46. Mouth Organs of Cricket, m, maxillae ; mp, maxillary 

 palpi ; I, labium ; Ip, labial palpi ; t, tongue. 



pair of palpi. The chief difference between the two 

 insects is to be seen in the appendage to the labium in 

 its centre, which is called the ligula, or "tongue." This 



