ticks may be altered by the size, number s, and density of available 

 hosts. Further research on this subject is stixjngly indicated. 



In the introduction to this section it has been stressed that 

 many Hyalomma populations survive in inclement environments and 

 are greatly affected tjy extremes in temperature, humidity, and 

 condition of host nourishment, as well as by the wide wandering 

 of their hosts over thinly populated, inhospitable xeric areas. 



Much more collecting, observing, and careful identification 

 is necessary before the ecology of niost species in this genus can 

 be adequately determined. The value of innumerable published 

 reports on the biology of the genixs is vitiated by the inaccuracies 

 in identification. 



Extraordinary survival factors ple^ a large part in permitting 

 these ticks to exist and even thrive where few or none others live. 



The life cycle of hyalommas may be greatly lengthened in un- 

 favorable climatic conditions, or shortened tinder optimum condi- 

 tions. Nuttall (1915) kept adult specimens alive without food 

 for approximately two years and observed copulation and feeding 

 after this period of starvation. Nuttall (1920) also found the 

 capacity for regeneration of lost appendages and injxired mouth- 

 parts to be greater in Hyalomma ticks than in most others. A 

 certain anount of hybridization is possible though curiously mis- 

 formed individxials may result; these and other greatly misformed 

 specimens that have still survived are reviewed by Pervomaisky 

 (19508,1950. 



Special attention is called to the discussion below of the 

 two-host, summer-feeding H. detrit-um , and its biological race 

 H, scupense which is a single-host, winter-feeding form with 

 slight morphological differences in most of its range (page 



DISE&SE RELATIONS 



Adult Hyalomma ticks, except H. aegyptium , are today chief- 

 ly parasites of domestic animals wEerever they are found, and, 

 as STich, are of considerable economic importance. Hyalommas 



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