Common Insect Enemies 99 



spreading typhus long before their body-dwelling descendants 

 evolved. But, be that as it may. Kill the head louse! Get 

 rid of him! At best he is a useless parasite; at worst he is a 

 deadly killer. 



Before the days of DDT, various remedies for the treat- 

 ment of lice were used. These included larkspur lotion, kero- 

 sene in either vinegar or olive oil, and derris powders and 

 lotions. With any of these materials, two or more treat- 

 ments are required because they do not kill the eggs and they 

 are not long lasting. Therefore, after you kill the lice you 

 have to wait until the eggs hatch and then try to catch the 

 new-born youngsters before they have a chance to enjoy their 

 love life and start raising families. 



If you'll just remember that DDT has long-lasting prop- 

 erties, you can readily see why it is effective against the head 

 louse as well as the body louse. So grab the carton of 10% 

 DDT powder and shake it thoroughly into Johnny's hair. He 

 may object to having his brunet locks suddenly assume a gray- 

 ish appearance, but he will forgive you when you explain 

 that he will not have to wash his hair for at least ten days. 

 The reason for this is that DDT has one thing in common 

 with the other louscicides — it does not kill the eggs. There- 

 fore, the powder must be left in the hair long enough to kill 

 the young lice from all the eggs as they hatch. 



If Johnny happens to be one of those unusual boys who 

 insist on washing their hair the day after treatment, a second 

 application of DDT powder should be made about 8 or 10 

 days after the first in order to get rid of the animal life that 

 hatches from the eggs left in his hair. The lice that hatch 

 during this 8- to 10-day period will not complicate the prob- 

 lem by laying more eggs, for it takes at least 10 days, and 



