THE SOUTHEEN PINE SAWYEB. 



53 



transformations (figs. 19, c, 20). The unfinished arm of the "U" is 

 usually extended by the larva to within about one-quarter of an inch 

 of the surface of the wood. When the larva pupates, the head of 

 the pupa IS turned toward the end of the chamber. When the pupa 

 changes to the adult, the beetle extends the chamber to the surface of 

 the wood and through the bark, if the bark is still upon the tree or 



Fig. 21. — The pine sawyer: Section of pine showing, at right, mass of twrings and 

 refuse paclied under bark (barli; removed) by the larvae and channels made 

 through the mass by the larvse. o, Entrance hole of larva in wood; 6, scored sur- 

 faceof wood; c,egg pit; d, emergence hole. About one-half natural size. (Original.) 



log, boring a perfectly round exit hole usually about three-eighths of 

 an inch in diameter (figs. 19, 21, 22), thereby escaping to propagate 

 the species in another tree or trees. 



NATUBAI, ENEMIES. 



Monoihammus titiUator is preyed upon by larvse of the coleopterous 

 family Trogositidse; by the larva of an elaterid beetle of the genus 

 Alaus, and by a species of Bracon which has been determined as new 

 to science. None of these, however, has been powerful enough, so 



