206 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



4. The genus Haemogmnasus is distinguished from Euhaemoga- 

 masus only in that its species possess accessory sternal setae. As each 

 of the following possess only the usual sternal setae, they are here 

 transferred to genus Euhaemogamasus : H. horridus Michael, 1892 ; H. 

 oudeviansi Hirst, 1914 ; H. quadrisetatus Vitzthum, 1926 ; and H. har- 

 heri Ewing, 1925. 



5. H. harperi and E. liponyssoides occidentalis are described as 

 new. 



6. The new genus Ischyropoda is proposed, and /. spiniger and /. 

 armatus are described as new species. 



7. Original descriptions are given of the male and nymph of H. 

 alaskensis and E. harberi as well as the nymph of E. liponyssoides. 

 The male of the latter species has never before been figured. 



8. In my opinion there is not sufficient evidence to indicate that 

 Acanthochela chilensis Ewing, 1933, should be placed in the Haemoga- 

 masinae. This species was described from four female specimens 

 taken from an opossum at Lota, Chile, in 1929, and it has not been 

 collected since. Condition of the specimens on the type slide is such 

 that it is impossible to determine the structure of the epistome or 

 chelicerae. Because of this, and as there are no males, nymphs, or 

 larvae available for study, it is proposed that the genus and species 

 be transferred to the subfamily Laelaptinae Tragardh, 1908, where 

 setation of the sternal shield alone would serve as a distinguishing 

 characteristic. 



MORPHOLOGY 



Each species description in their paper is based upon a study of 

 several aspects of morphology common, in general, to all members of 

 the subfamily. 



1. Dorsal shield. — Nearly covers dorsal surface in most species; 

 setae, present over entire surface of shield, are usually larger in apical 

 region, where a pair of conspicuously large apical setae is present on 

 the anterior margin of the shield; setae may vary in size and num- 

 ber and may be smooth or barbed; several pairs of dorsal pores 

 may be present near the margins of the shields ; fine reticulations on 

 the shield produce the effect known as sculpturing. 



2. Dorsal hody setae. — ^Those setae lateral and posterior to the dor- 

 sal shield; frequently larger and more often barbed than setae of 

 shield; usually largest at posterior body margin, where two or three 

 pairs may be conspicuously long. 



3. Tritostemwrn. — Shows little variation ; lacinae may be smooth or 

 barbed. 



4. Presternal area. — Sculptured, with transverse sutures, which in 

 some species possess tiny, posteriorly directed spines. 



