THE ACAEIXA OR MITES. 



63 



Some writers have elevated the ticks to a position higher than a family or super- 

 family; usually to a suborder; thus Marx called *hem Cynorhaestea, and LahiUe Arpa- 

 gostoma, while Koch and others have designated them an order, Ricini. Their rela- 

 tionship to the Parasitoidea is such that they should not rank higher than a superfamily. 



The Ixodoidea are readily di\T.ded into two 

 families: 



No scutum; no ventral shield; mouth parts 



of adult not prominent from above; 



no pul villus to tarsus in adults; stig- 



mal plate between coxae III and 



IV Argasid.e. 



Scutum present; sometimes ventral shields; 



mouthpartsof adult prominent from ^'^t^-'£J^' "-^ -i^ ^- 



above; pulvillus to tarsus of both ^^^^^ j ^^ *^' ~ ^S^ 



adults and young; stigmal plate be- rj* *" 



hind coxae Ixodid^. ^ ' 



The Argasidae, containing but few genera, are #^/ 1 ».~, ^ * 



in some ways intermediate between the true ticks w^ A » f j-';'"^ - % \ 



(Ixodidae) and the Dermanyssidae. The skin is jiV^^ 1 "^ ' 



usually covered with granulations or deeply pit- ^-^ ^^ ^ 



ted, and the head and mouth parts are hidden ,f -^ W. >i - ^- 



beneath the anterior part of the body. They are W^ vy^^:&?&r ■ 

 nocturnal in habit and feed on the blood of mam- 

 mals (including man) and bii'ds. Unlike the true 



ticks, the females of this family do not become 



^, ,. ^ 1 1 -^1 1 1 ^ mi o^i Fig. 117.— Dermacmfor aZfejpjcitts; Male, 



so greatly distended with blood. There are three (Original ) 



genera and two subgenera in our fauna. 



1 . Margin of body thin and acute Argas. 



Margin of body rounded 2 



2. Body with many short stiff bristles; mouth parts weak and indistinct Otobius. 



Body without bristles; mouth parts well developed Ornithodoros 



Argas has two subgenera as follows: 

 1. Body as broad or broader than long Carw. 



Body much longer than broad Argas. 



Ornithodoros may also be divided as follows: 

 1. A lateral flap each side of mouth parts AJectorohius. 



No such flaps Ornithodoros. 



In the female argasids the genital orifice is transverse; in 

 the male it is crescentic. The females may engorge and 

 oviposit several times. 



It is to the genus Argas that the famous ' ' miana ' ' bug of 



Persia {A . persicus Oken) belongs. It lives in houses, and its 



puncture was declared by the early travelers in those regions 



to produce startling results — convulsions, delirium, and even 



death follo^ving its attack. Specimens kept in Europe for 



Fig. lis.— Shield of Rhipice- experiment have failed to produce these dire consequences, 



phaius sanguineus, female, but there is such a wealth of testimony as to the dangerous 



(Original.) ^^^^^ ^^ ^-^^ ^-^^ • ^^ Persia that possibly in that country the 



"miana" bug may at times carry the germs of such disease. The European species 



Argas rejlcxus, Fabr. commonly infests pigeons, but has been known to attack man ; 



not, however, with serious results. This species has been recorded from our country, 



but perhaps erroneously, as specimens have not been seen by acarologists. Our 



common species of this genus, Argas miniatus Koch (fig. 103), {americana Pack.) is 



found in the southern parts of the United States from Texas to California, and often 



does a great deal of injury to poultry. It occurs in other parts of the world, probably 



SSS54°— 15 5 



