82 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I28 



however, it became easy to collect this species by picking specimens 

 up singly by fine-pointed forceps. 



This persistence of attachment after death of the host has been 

 noted for other species of Gahrliepia. Gater called attention to this 

 habit in G. fletcheri in the original description (1932). Fuller (1952) 

 refers to similar but unpublished observations made by the U. S. A. 

 Typhus Commission in Burma regarding undescribed species (re- 

 ferring to G. exilis, new species, q.v., and the small form of G. flet- 

 cheri occurring in Assam and Burma). 



Perhaps when we learn more about the true hosts, attachment 

 sites, and ecological requirements of these chiggers, they may be col- 

 lected more readily. There is another possibility worth investigating, 



Table 2. — Number of specimens and hosts in type series of certain 

 ornate Gahrliepia 



Number of Number of hosts 



Species of specimens in 



Gahrliepia type series Individuals Species 



ornata Womersley, 1952 i i I 



insigne Womersley, igS2 i i I 



decora Womersley, 1952 7 I I 



picta, new species 3 3- 2 



tessellata, new species 8 5 4 



evansi, new species 4 3 2 



ampidlata, new species 6 2 I 



gramdata, new species 6 5 3 



and that is that these species may be burrowing forms, similar to 

 G. penetrans (q.v., above). 



The function of the deeply pitted scutum can only be guessed in 

 the present stage of our knowledge, if indeed there is a function. If 

 the anterior end of a chigger is deeply inserted into a hair follicle or 

 skin (as G. laciniata), or if the species completely burrows into the 

 superficial layers of the skin (as G. penetrans), the large pits of the 

 scutum may serve to entrap and hold a useful supply of air. It should 

 be pointed out, however, that scrobiculate scuta are not known to 

 occur in chiggers of the genus Hannemania, which burrow into or 

 live under the skin of Amphibia, or in Apolonia tigipioensis Torres 

 and Braga, which burrows into the quills of chickens. 



When discussing host records of chiggers, one must bear in mind a 

 distinction between ecological and physiological host preferences. Eco- 

 logical host preferences are those infestations of chiggers which are 

 primarily due to the host's predilection for that specific habitat or 

 terrain which is also favored by the nonparasitic stages of the chigger. 

 A variety of mammals living in or entering that microclime may ac- 



