THE PASSING OF THE TREES 183 



4. "Glow-worms" (Lampyridae) , having the body 



elongate tapering to the ends, flattened on the 

 back, with well-developed legs and usually a pig- 

 mented skin. 



5. "White grubs" (Scarabaeidae) , having the short thick 



body bent double upon itself, so that the grub lies 

 on its side, the legs well developed, the white skin 

 bristly, and the blunt hinder end of the body 

 smooth and shiny. 



6. Pyrochroid beetle larvae (Pyrochroidae) , having the 



body very thin and flat, its sides parallel, the legs 

 well developed, the skin brown, and a pair of stout 

 upturned hooks at the end of the abdomen. 

 III. Fly larva (Order Diptera), having cylindric legless 

 bodies that taper from rear to front, the head being apparently 

 wanting. Three families commonly are found. 



1. Fungus-gnat larvae (Mycetophilidae), of minute size, 



white and soft, usually occurring gregariously 

 under bark. 



2. Snipe-fly larvae (Leptidas), of similar form but larger 



and with the pointed front end of the body of a 

 deep brown color, usually found in rotting wood 

 (fig. 702) 



3. Crane-fly larvae (Tipulidae), less tapering, more cylin- 



dric, with the head end more bluntly pointed, and 

 with a respiratory disc upon the rear end in the 

 midst of which may be seen the openings of a pair 

 of breathing tubes. Skin tough and more or less 

 leathery. 



IV. Horn-tail larvae (Order Hymenoptera) , having a 

 long smoothly-cylindric white body with a prominent spine 

 on the posterior end, rudimentary thoracic legs, and a 

 small but distinct head placed low down at the front end; 

 living in large clean-cut holes that are usually disposed in. 

 groups in dead or living trees. 



