140 PARASITES OF THE DOMESTIC ANIMALS 



Depending on the stage of engorgment, the color varies from Hght 

 reddish to dark brown. The capitulum has four long hairs, all directed 

 forward. The adult females are about 8.5 mm. (5/16 of an inch) in 

 length. The males are slightly smaller, but are not easily distinguish- 

 able. 



Occurrence and Habits. — Commonly called the "fowl tick" or 

 " adobe tick," this species is widely distributed. It is a parasite of fowl in 

 Europe, Asia, Africa, and Australia, in Mexico and the Southern United 

 States. In its habits it is comparable to the bedbug, commg out to 

 feed upon its host at night and retreating after engorgment to cracks, 

 crevices, or other darkened hiding places to remain during the day. In 

 these retreats the females deposit large, reddish brown eggs, usually 

 several layings, in masses containing up to a hundred or more eggs in 

 each. Herms (1915) gives the further life history as follows: "Hatching 

 takes place in from three to four weeks. The larvee are six-legged and 

 very active, attacking a host apparently as readily by day as by night. 

 Once attached the larvae feed for about five days, occasionally longer, 

 remaining firmly attached during this time. At the end of this feeding 

 period the larvae detach themselves and then crawl away from their 

 host, hiding in some convenient crevice near by. The larvae molt in 

 about a week, when the fourth pair of legs appears and they are now in 

 the first nymphal stage, appearing like miniature adults. Nocturnal 

 feeding now takes place and in ten or twelve days another molt 

 occurs and the second nymphal stage is reached. Again the tick at- 

 taches itself, being now able to engorge itself in about an hour; again 

 after the expiration of something over a week a third molt takes place 

 and the adult stage is reached. The adults are able to engorge them- 

 selves in from twenty to forty-five minutes." 



Effect. — When attacking in large numbers these parasites extract 

 large quantities of blood and, furthermore, cause much irritation and 

 unrest among the flock. As a result the animals become unthrifty, 

 weak, and nonproductive. 



Argas miniatus has been proven to be the carrier of the spirochete 

 (Spirocheta gaUinarum) causing fowl spirochetosis or Brazilian sep- 

 ticemia of fowls (p. 327). 



Control. — For the eradication of this pest the same general methods 

 may be taken as recommended for bedbugs of the hen house (p. 92). 

 The ends of roosts should be repeatedly covered with tar or wrapped in 

 waste soaked Avith crude oil. Nesting and trash should be burned and 

 the interior sprayed with kerosene. All woodwork about the buildings 

 should be free from bark, as this affords a favorable hiding place for the 

 ticks. It is well to repeat the treatment with kerosene at least once a 

 month during the season that the ticks are active, 



2. Otobius megnini (Ornithodorus megnini, Fig. 80). The Spinose 



