rsinge of temperature and humidity conditions. Host flight habits 

 account for the wide distribution of A, vespertilionis , but we 

 are not aware that host migration is a factor in mixing populations 

 from widely differing ecological situations, 



European and South African populations exist under temperate 

 climatic conditions with pronounced seasonal changes and with 

 moderate to heavy rainfall. Those of Egypt and of northern Sudan 

 normally tolerate the most extreme arid niches in which any arthro- 

 pod is known to survive. Their engorged larvae, however, are 

 found usually among moist dung or in dung between crevices of 

 bats' retreats. Just where females commonly oviposit in natiu*e 

 and where unengorged larvae rest before seeking a host has not 

 yet been satisfactorily determined 



Throughout Europe and Africa interstices in the walls of bat- 

 infested caves and buildings are the most common habitats of A, 

 vespertilionis . They may also be found in tree holes and in other 

 situations frequented by certain bats. In Cairo a specimen, re- 

 calling Robert Burns' wee louse, has been taken from a worshipper 

 during church service by an observant but distracted friend sit- 

 ting behind. In Iraq, Pat ton (1920) reported the same or a closely 

 related species in Bedoiiin tents in which bats presumably rested by 

 day, 



Egyptiaji specimens hide aJ-one or clustered in large or small 

 groups usually well concealed between shale or in crevices of 

 walls. Some individuals are observed wandering openly on the walls. 

 Unconcealed individuals are noted much more frequently in those 

 caves or niches that only erratically harbor a few bats than in 

 large caves where many bats usually roost. Possibly our entry 

 into caves infrequently visited by any animals induces these ticks 

 to investigate the possibility of a meal. 



Small numbers of the round bat-argas frequently are found in 

 niches in the most unexpected cliff sides where a few old pellets 

 of dung indicate that hermit bats such as Otonycteris h. hemprichi 

 occasionally spend the day. These ticks lead a most uncertain 

 existence and often wait months on end for a host, as revealed 

 by their compressed bodies and by the age and scarcity of hosts' 

 dung in these places. 



_ 108 _ 



