3*0 



COLLEGE ZOOLOGY 



The family TROMBIDIID^E includes the harvest mites or 

 " chiggers " (Fig. 321). These little creatures are transferred 

 by contact from plants to the bodies of man and other animals. 



They burrow into the skin, 

 with painful results. 

 Treatment with a one or 

 two per cent solution of 

 carbolic acid is the proper 

 remedy. The poultry 

 tick, Dermanyssus gallince 

 (Fig. 322, A) belongs to 



FIG. 321. Order ACARINA. Harvest- the family GAMASnXE. It 

 mites or "chiggers." Leptus irritans on sucks the blood of chickens, 

 the right; L. americana on the left. (From . . 



Osbom, after Riley.) and is a pest on poultry 



farms. 



The family IXODID^: contains a number of injurious species. 

 The cattle tick, Boophilus (Mar gar opus) annulatus (Fig. 322, B), 

 is perhaps the most important. These ticks cling to the skin of 

 cattle with their strong mouth-parts, and suck the blood of their 

 host. When full grown the females drop to the ground and lay 

 from 2000 to 4000 eggs; these soon hatch, and the young crawl 

 upon a blade of grass and wait for cattle to come past to which 

 they can fasten themselves. The principal injury done by the 



A B 



FIG. 322. Order ACARINA. A, poultry tick, Dermanyssus gallina, young. 

 B, cattle tick, Boophilus annulatus. 



