100 



APPLIED ENTOMOLOGY 



Family Lampyridae (Fire flies, etc.). In several ways the insects 

 belonging here appear to be among the simplest of the beetles (Fig. 80). 

 Their bodies are quite soft as compared with the others; the abdomen has 

 been little reduced, seven or eight segments being perceptible, and the 

 larvae are quite simple and feed on small insects and other animals such as 

 snails, either living or dead. 



Only a few members of the group are often noticed except by ento- 

 mologists, but those which attract attention are familiar by the light they 



produce at night, which has given them the 

 names "fire flies," "lightning bugs," etc. The 

 light is produced by specialized areas of the 

 body, frequently at least on the underside of 

 the abdomen near its tip. The light itself is 

 not persistent but comes in flashes and is dis- 

 tinctly yellow in most cases. It is believed to 

 be produced by the oxidation of granules in the 

 outer layer of the luminous organ, the oxygen 

 being supplied by the tracheae, and under 

 control of the nervous system. In some species the adult female is 

 wingless so that its light appears as it crawls on the ground, and such 

 individuals are often called "glow-worms." 



Other insects and animals also have luminous organs, but the lights 

 they produce are probably less frequently seen than those made by Lam- 

 pyrids, these being widely distributed and very abundant insects. 



FIG. 80. Examples of 

 Common Lampyrid Beetles, 

 about natural size. 



(Original.) 



FIG. 81. Common Ground Beetle 

 (Harpalus caliginosus Fab.), natural 

 size. (Original.} 



FIG. 82 . European Calosoma Beetle 

 (Calosoma sycophanta L.) and its larva, natural 

 size. (Original.) 



Family Carabidae (Ground-beetles). These insects are active, running quickly 

 over the ground, and the group is a large one containing many different species, 

 over 1,200 of which are found in the United States (Fig. 81). They feed mainly 

 at night, hiding by day, and the majority are dark colored or black, though a few 

 have bright colors. They are predaceous, both as larvaB and adults in most 

 cases, though a few have been known to depart from their usual habits and feed on 

 berries and seeds. One species (Calosoma sycophanta L.) has been brought to this 

 country from Europe as it feeds to quite an extent on the caterpillars of the Gypsy 



