NO. 6 CHIGGER SUBGENUS GAHRLIEPIA — TRAUB AND MORROW 79 



and position of scutal setae, they are remarkably uniform in certain 

 particulars. The sensory setae of the legs, described for G. exilis, 

 new species, are the same in all known chiggers of the subgenus Gahr- 

 liepia, and incidentally the same pattern occurs without variation in 

 the subgenus S chongastiella. (The subgenus Walchia has not yet 

 been studied by us in this regard.) This may very well prove to be a 

 generic character. This group of chiggers is, therefore, in marked 

 contrast to Tromhicula, in which the setal pattern varies considerably 

 and in which highly modified sensory setae may be present. The 

 palpal setal formula is an excellent taxonomic character in Trom- 

 hicula because of the many specific variations one encounters, but 

 here again the subgenus Gahrliepia seems to be much more consistent. 

 The palpal femoral seta is barbed in 28 of the 33 species. (The excep- 

 tions are: rutila Gater, 1932; ciliata Gater, 1932 ; romeri Womersley, 

 1952 ; lawrencei Jadin and Vercammen-Grandjean, 1952 ; and philipi 

 (Jadin and Vercammen-Grandjean, 1952).) The dorsal seta of the 

 palpal tibia is nude in 26 species, while the lateral seta of this tibia 

 is barbed only in G. exilis, new species. 



It is difficult to place the species of G. (Gahrliepia) in natural 

 groups. At first thought it would seem that an obvious division would 

 be to classify the species as scrobiculate ("ornate") versus nonscro- 

 biculate. However, there is no real evidence to indicate that the scro- 

 biculate species are truly related to one another. On the contrary, 

 the Gahrliepia with scrobiculi may more likely prove to form a hetero- 

 geneous group. For example, in G. evansi, new species, tessellata, 

 new species, tuberculata, new species, ampullata, new species, pene- 

 trans, new species, ornata Womersley, 1952, and decora Womersley, 

 1952, coxa III is nearly or actually as broad as long. However, in the 

 other 4 "ornate" species, this coxa is one and two-tenths to one and a 

 half times as long as broad, thus agreeing with the vast majority of 

 nonscrobiculate species. The exceptions in the last group are interest- 

 ing — 3 of the 4 species in which the PL setae are displaced so as to be 

 very close to the ALs also have very broad coxae III. The ratio of 

 PW to the length of the third tarsus varies in this subgenus from 

 0.75 to 1.84. Again no systematic groupings are possible, for both 

 the extremes noted appear in scrobiculate species. Half of the known 

 forms have only 4 usurped setae, but these chiggers share no other 

 exclusive feature in common. It is apparent that as yet too little is 

 known about this subgenus of trombiculids to properly delimit groups 

 of species. 



An African genus near Gahrliepia is discussed at the present time 

 in order to compare it with Gahrliepia and to avoid bibliographic 

 difficulties in future citations. 



