THE INSECT WORLD. 



237 



of an inch in length are the grain weevils, belonging to the genus 

 Calandra. These are almost cosmopolitan, and infest stored 

 grains of all kinds. They are black or brown-red in color, quite 

 slender, and on a very small scale resemble the ' ' corn bill-bugs' ' 

 in sculpture. They can be easily controlled by the use of bisul- 

 phide of carbon poured on the grain in bins or other receptacles. 



Fig. 244. 



Sphsnophorus oc/ireus.— Adult, larva, and work in roots of Scirpus. 



covering with canvas or similar material to prevent the too 

 rapid escape of the fumes which gradually permeate the entire 

 mass of grain, killing everything in it. 



Closing the series we have the bark-beetles, or Scolytids, some 

 of them called shot-hole borers from the little round holes with 

 blackened edges which they make in wood and bark. Many 

 species make prettily -figured burrows between the bark and sap- 

 wood, while others bore into the solid wood, making longer or 

 shorter galleries. Most of the species attack forest-trees, and for 

 them reference should be had to Dr. Packard's work already cited. 



