64 



REPORT 108, U. S. DEPARTMENT OF AGRICULTURE. 



carried on poultry. Chickens, badly infested, droop, refuse to eat, in a few days drop 

 down, and finally die. The tick is red-brown in color, the margins of the body are 

 rather sharp, and above scarred and pitted in a scarcely regular way. It has also been 

 taken on diseased quails in California, and thought to cause the disease. 



Fig. 119.— Palpus of iSftipi- 

 ccphalus. (Original.) 



Fig. 120.— Shield of nymph of Rhipi- 

 ccphalus. (Original.) 



FlQ. 121.— Rhipicephalus pulchellm: 

 Male. (Original.) 



The eggs of the Argas miniatus are laid in cracks and cre\-ices of floors, walls, etc.» 

 The young larvae are at first colorless, but after feeding become darker; they may 

 remain on a fowl for 10 days, but usually drop sooner to transform to the nymph; the 

 larvae usually drop at night, so that the nymph will be near the roosting quarters of the 

 fowls and have no difficulty in finding a host. The adults do not feed so often. 



This species, as well as other argasids. can live a 

 long while without food. Unfed specimens have 

 remained alive for over two years. The chicken 

 tick in Brazil transmits a blood parasite (S pirochaeta 

 marchouxi) which is usually fatal to poultry, and a 

 similar spirochsetosis has been observed in poultry 

 in other countries, produced by the same or a re- 

 lated parasite. Perhaps the best remedy is to spray 

 the inside of the chicken house with kerosene or 

 benzine, then whitewash or dust with carbolated 

 lime, and finally daub the ends of the roosts with 

 coal tar. Isolating the roosts by suspending them 

 on stout wire, or by placing a barrier of cotton 

 waste soaked in oil around each end. will also be 

 helpful. 



Two species of Argas have the body broader than 

 long. One {A. vespertilionis Latr.) occurs on bats 

 in Europe and North Africa. Pocock has re^^ved 

 Latreille's generic name, Caris, for this species; the other broad form is A. transversvs 

 Banks, which occurs on the large tortoises of the Galapagos Islands; they may bo 

 considered to represent a subgenus. 



The genus Ornithndorns includes a number of spocios distributed throughout the 

 warmer regions of the world. Several species that inhabit houses can inflict a severe 

 bite and are well-known pests in nearly all tropical countries. They can secrete 

 from their coxal glands an alkaline fluid which tends to prevent the coagulation of 

 blood. 0. coriaceus Koch occurs in California on cattle; it also attacks the herders, its 

 bite causing large swellings that are very painful and remain for a week or more. 

 This 8i)ecic8 has eyes, or ocelli, each side above coxaj II. It is locally called "paja- 

 huellos. " 



