31 



are much distended in size, with the coxae widely separated, lay a 

 single large batch of eggs, and moult twice only, viz. when leaving 

 the larval and nymphal stages. The Argasidce have a flattened 

 appearance like that of bed-bugs, are mostly found in warm climates, 

 and are nocturnal in habits. 



The life-history of a tick is sharply divided between a free and a 

 parasitical existence. In the first stage it can live without a host for 

 long periods. Mr. Wheler records a case of a headless female of 

 Ixodes rid/iHS, lacking all the mouth organs, surviving for over a year 

 in captivity, and eventually lost sight of. 



Of the Argasidce the genus Argas has six well-established species 

 — persicus, transgariepinus, hru7npti^ cequa/is, rejiexiis, and vesper- 

 tilionis. The two latter are British. 



The genus Ornithodoros has no indigenous British species, and 

 comprises the following : savignyi, tnoidmta, coriacei/s, iiiricata^ 

 ialaje, pavimeiitosus, er?-aticus, tholozaiii, lahore7isis, furcosjis, and 

 megni?ii. 



Argas persicus is a well-known species, and widely cosmopolitan. 

 It lays eggs in batches in cracks and crevices of walls, about a week 

 after feeding, in warm weather, and hatching begins in three weeks. 

 It has been known to live three and a half years in captivity. Its 

 bite is dangerous to man, one fatal case being recorded after twenty- 

 four hours. It makes serious ravages on fowls, masses of persicus 

 being found under the wings, causing rapid death of the host. The 

 remedies applied for their destruction are kerosene, turpentine, hot 

 coal tar, and burning the habitats. 



Argas reflexus infests pigeons, hiding in the pigeon-coops, and in 

 cracks of walls and wood-work, and attacking at night. Its habitats 

 are Europe and North Africa. 



Argas vespertilionis has been found in England, parasitical on 

 bats. 



Ornithodoros savignyi, known in South Africa as the "tampan," is 

 closely related to A. persicus, and is a great pest to man and animals, 

 frequenting the native huts. 



Of the family Ixodidce. the group Ixodcc comprises the genera 

 Ixodes, Ceratixodes, Eschatocephaliis, Aponomma, Amb/yomma, and- 

 Hyalonwia. 



Of the group Rhipicephalce we have the genera Rhipicephalus, 

 Hoemaphysalis, and Derinacentor. 



Professor Neumann describes over sixty species of the genus 

 Ixodes. 



I. ricinus is the best known of our British species, and is 

 commonly called the "grass-tick." It was named reduvius by Leach. 

 The investigations of Mr. E. G. Wheler, late of Alnwick, have proved 

 conclusively that this tick is the cause of " louping ill " in sheep, the 

 symptoms of which are loss of muscular power, cramp, trembling, 

 paroxysms, reeling, etc. The adult male (PI. IX, fig. 3), is about 

 2 "35 mm. to 2-80 mm, in length, the female (PI. IX, fig. 4) from 



