14 



Circular 338, U. S. Department of Agriculture 



thick lather of whale-oil or fish-oil soap, or an emulsion of 8 parts 

 of the soap to 1 part kerosene may be used, but kerosene must be used 

 witli caution, the emulsion well made, and the anim^al not allowed in 

 the bright sunlight for several hours after treatment. AMien 

 weatlier conditions do not permit dipping Or clipping, or when 

 clipping is undesirable, palliative measures, not very effective in 

 eradicating lice, may be used. Such measures consist in dusting 

 the hair thoroughly with pyrethrum powder (buhach or ordinary 

 Persian, Dalmatian, Caucasian or Oriental insect powder) , allowing 

 it to remain on for half an hour or so, and then combing or brushing 

 it out, with the dead and stupefied lice, on to a newspaper, the paper, 

 lice, and powder then being burned. This treatment must be re- 

 peated a number of times in order to keep down the lice. Other 

 powders, containing such insecticides as naphthalene, sulphur, and 

 tobacco, may be used in the same way. 



When only biting lice are present they may be destroyed by dusting 

 sodium fluoride into the hair and leaving it on, the animal not 

 being washed for the next 10 days. One application will usually 



destroy all the lice. 

 The animal should 

 be prevented from 

 licking itself, as 1 

 gram (about one- 

 fourth teaspoonful) 

 of sodium fluoride 

 will kill a dog of 

 average size. This 

 chemical is not of 

 value against suck- 

 ing lice. 



FLEA INFESTATION 



Cause. — I n the 

 United States there 

 are four species of 

 fleas which are of in- 

 terest as parasites of 

 dogs. These include 

 two very similar 

 species, called respectively the dog flea, CtenocephaJus canis, the cat 

 flea, Ctenocephalus felis^ the common human flea, Piilex imtane, 

 and the sticktight or chicken flea, Echidnophaga galJinacea. 



The dog flea (fig. 12) appears to be the most common flea attack- 

 ing dogs and people in the eastern portion of the United States. 

 It moves about on the host animal between feeds. transfei*s readily 

 from clog to dog and from dog to man, but is disposed to remain 

 on some host animal rather than off. The eggs laid by the flea fall 

 off' the host animal and in the course of time hatch, giving rise to 

 elongate larvae which feed on the animal and vegetable content of 

 the trash present in the dog's bedding or in other places frequented 

 by dogs. In time the larva forms a sort of cocoon, and after a period 

 in tlie pupal stage the insect emerges as an adult flea. Tn the house 

 the development from q^^ to adult commonly takes place in carpets 

 and rugs, aud in the trash in cellars and basements. The closely 

 related cat flea has a similar habit and life history. 



Fig. 12. — The do; 

 eral view 



flea, Ctenocephalus canis. Female. Lat- 

 Enlavged. From Martini, 1923 



