182 NATURAL HISTORY OP THE FARM 



squeeze in under the loose bark; woodpeckers, that cut 

 deep holes to find the borers; and raccoons and bears 

 that tear rotten logs to pieces with their claws, searching 

 for grubs to eat. Each fallen log is a center of considerable 

 resident population, and entertains numerous foreign visitors. 

 A few of the more common and characteristic residents are 

 shown in figures 70 and 71. 



The following brief statement of group characters may 

 further aid in their recognition. Most of the resident 

 insects found in logs will be: 



I. Caterpillars, (Order Lepidoptera) having a long cyl- 

 indric body, with a brown shield covering the first segment 

 behind the head, and a tuberculate, spinous skin. These are 

 moth larvas fig. 70*. 



II. Beetle larvae, (Order Coleoptera) having a distinct 

 head, usually small legs also, no brown shield on the first 

 segment after the head, and a great variety of form and size. 

 Beetles are the most "important of wood-destroying insects, 

 and a number of the families of beetle larvae may be recog- 

 nized by the following characters : 



1. The true borers (members of the families Buprestidae 



and Cerambycidae), having the long, straight body 

 greatly widened and flattened toward the front 

 end, the skin naked, pale and wrinkled, and the 

 legs rudimentary. These perforate the hardest 

 woods. 



2 . The engraver-beetles (Scolytidae) , having short, thick, 



arcuate bodies that are usually legless, naked, 

 wrinkled, and white. 



3. "Wire-worms'' (Elateridae), having very smooth 



cylindric, elongate bodies, small legs, shining 

 yellowish or brown skin, and a horny disc ter- 

 minating the abdomen above, the margin of the 

 disc being toothed or sculptured (fig. 'joy). 



