OUTLINES OF ENTOMOLOGY. 55 



attracted to lamplight, and I have, on several occasions, seen the side- 

 walks around the electric light posts almost covered with dead and dis- 

 abled specimens of the beautiful, metallic-green Calosoma scrutator, 

 Fabr. As they are very swift runners, most species make but little 

 use of their wings ; indeed, the latter are in some cases entirely unde- 

 veloped, and the elytra are firmly joined at the suture on the back. 



The larvae are elongate, somewhat flattened grubs, having the body 

 protected on top by horny plates, and in some instances terminated in 

 a pair of branching spines or forceps-like appendages. They burrow 

 back and forth just beneath the surface of the earth, and destroy many 

 of the soft larvae of fruit and leaf-feeding species that have entered the 

 ground for transformation. 



Among the most beneficial species is the Fiery Ground-beetle (Calo- 

 soma calidium, Fabr.), a large and elegant beetle of a black color, with 

 elytra (wing covers) thickly dotted with shining, impressed, coppery 

 spots (see Fig. ). This beetle preys upon cut-worms, and its larvae, 

 having the same habit, has been called the " Out-worm lion." Another 

 smaller species, Lebia grandis, with a red-brown thorax, and legs and 

 dark-blue wing covers renders us good service in destroying the larvae 

 of the Colorado potato-beetle. 



One species, a little larger than the above, but clo&ely resembling 

 it in form and color, is called the Bombardier beetle (Brachinus fumaus), 

 as it has the singular power of discharging a volatile and pungent fluid 

 from the tip of the abdomen, which rises in the air like a little puff 

 of smoke. It is a means of defense against its enemies. 



The Water-tigers are quite common in ponds and sluggish streams. 

 The beetles are easily recognized by their broad, flat, ovate, pol- 

 ished bodies, often an inch and a quarter in length, and by the hairy, 

 oar-like shape of the hinder legs. When disturbed these beetles dive 

 deep under water, carrying with them a bubble of air which sustains 

 respiration until they again rise to the surface. Their larvae are long 

 and cylindrical, with a pair of breathing tubes at the posterior end that 

 can be protruded above the surface of the water. The head is armed 

 with powerful, scissor-like jaws which are kept in almost constant mo- 

 tion. They are very savage and greedy, feeding upon other aquatic 

 insects, tadpoles and small fish, in some streams proving v^ery destruc- 

 tive to the latter. When full grown they crawl upon shore and enclose 

 themselves in earthen cells within which they change to pupae. The 

 perfect insects make their way into the water as soon as they emerge. 



The " Whirligigs " are another family of preying water-beetles 

 which, though allied to the Water-tigers, are distinguished from them 



