86 LOWER PTERYGOTA 



attacked with the assurance that eggs and newly hatched 

 young are not developing in some out-of-the-way corner. 



Moreover, the observations made on the length of time 

 required for the hatching of the eggs indicate that they 

 require a number of days at least, so that in repetition of 

 treatments intended to kill individuals hatched since a 

 former treatment a period of ten days to two weeks ma>' be 

 counted on as probably short enough. 





> 





Fig. 47.- 



-Trichodectes parumpilasus (biting horse louse). (Bull. 5, 

 Fig. 133.) 



It should always be borne in mind that lice must grow 

 from eggs laid by the adult louse, and can never originate 

 from filth or other matter. Chickens hatched in an incuba- 

 tor should be absolutely free from lice and remain so until 

 brought in contact with a lousy hen or put in a lousy chicken 

 house. 



The effect of these lice may be less important than the 



