INSECTS INJURIOUS TO CLOTHES 225 



bear special structures for the purpose and are put into 

 rapid motion, as we shall see. The large vein that runs 

 diagonally across each of the upper wings near their bases 

 is crossed with many file-like ridges. Also, not far from 

 the tip of each wing along the inner margin is a hardened 

 membranous portion which may be called the scraper or 

 drum. Thus each of the upper wings is furnished with a 

 file and a scraper. When the cricket desires to make his 

 chirping song, he elevates these wings at an angle of about 

 forty-five degrees and holds them so that the scraper of 

 one rests upon the file of the other. He then moves the 

 wings very fast from side to side, rasping the scraper of each 

 wing with the file of the other. This movement throws 

 the wings into vibration and produces the chirping sound. 

 Since the cricket can make sounds, we would have a right 

 to infer that it is endowed with the sense of hearing. Cu- 

 riously enough, there is an oval transparent disk on each of 

 the fore legs that undoubtedly serves as an ear or organ 

 for perceiving sound. 



Methods of control. Crickets are very fond of certain 

 liquids like beer and sweetened vinegar. It is said that their 

 extreme fondness for these liquids literally drives them to 

 drink ; for if deep glass vessels are half filled with a favorite 

 liquid and placed where the insects can easily get into them, 

 they can be trapped and drowned in great numbers. The 

 author has never had an opportunity to try this method 

 of catching crickets, but it is given on excellent authority. 



They may also be killed by poisoning pieces of fresh 

 carrots, parsnips, or potatoes with arsenic and placing 

 them about where the crickets will easily find them. Of 

 course great pains must be taken not to put the bait 

 where children can get hold of it. 



