INJURIOUS AND BENEFICIAL [NSECTS OF CALIFORNIA. 



497 



Sieve Nets. — Various types of sieve nets are used for capturing 

 aquatic insects, some in the form of a dipper and others with a net 



Fig. 492. — Pinned insects. The white ants at left are 

 pinned through the prothorax ; the dragon-fly at the right is 

 pinned through the mesothorax and has the wings spread. 

 (Original) 



fastened to the top of a rake. The teeth of the rake serve to loosen 

 up the bottom of the pool or stream and dislodge the insects which 

 are captured in the net just 

 above. 



Traps. — Large numbers 

 of insects are attracted by 

 light and may be captured 

 automatically by light traps. 

 One form of light trap is 

 simply a lantern suspended 

 over a pan or tub of water 

 into which the insects fall 

 in their flights about the 

 light. Moths and delicate 

 insects, however, are usually 

 ruined in the water and 

 other insects are often dis- 

 figured by the bath. An- 

 other type, especially for 

 moths, consists of a large 

 funnel which leads into a 

 cyanide or chloroform jar 

 and the mouth placed near 

 a reflector in front of a light. 



The insects strike against the Fig. 493.— Pinned insects. Gi 



p -i a a ■ + +1 crickei pinned through the mesothorax. I wn 



tunnel ana arop into me methods ,,,■ spre ading also shown. 



killing jar beneath. (Original) 



Many beetles arc effectually captured by traps baited with spoiled 



and decaying meats, fruits and vegetables. A very inexpensive trap 



consists of a can or jar sunk into the earth until the top is even 



32— 13G64 



