594 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii4 



margins sublinear and gradually converging distad to narrow but 

 evenly rounded apex. 



Anellus membranous, unarmed; juxta absent, although upturned 

 flap at base of aedeagus may be mistaken for one. 



Aedeagus of medium length, slender, tubular, asymmetrical, sub- 

 glabrous, approximately linear in dorsal and ventral aspects, sinuate 

 and irregularly curving ventrad through angle of approximately 90° 

 in lateral aspect, gradually and evenly narrowing distad from near 

 base to near apex, ventral surface of base broadly and evenly expanded 

 ventrad into flattened flap with apical half curving sharply through 

 angle of 180° to rest against ventral surface of basal half (not to be 

 mistaken for juxta); apex narrowing, subacute, with small dextral 

 opening, with small ventral area minutely spinose. 



Vesica small, membranous, unarmed. 



Type. — Type cT in the British Museum (Natural History). Addi- 

 tional type material at the Academy of Natural Sciences of Philadelphia. 



Type locality. — Bosque Co., Tex. 



Distribution. — Southern United States. Arizona eastward to 

 Florida. 



Sources of material. — American Museum of Natural History 

 (2 cf cf); California Academy of Sciences (IcT); Cornell University 

 (1 cf); Denison University (1 cT, 2 9 9); Illinois State Natural 

 History Survey (3 cf cf , 1 9). 



Specimens examined. — 11 (8 cf cf , 3 9 9), from 5 localities: 



Arizona: Boulder Springs, Mohave Co., cf, 9 (July 1-15, 1921, 9 with 

 three mites on eyes, O. C. Duffner); Hualapai Mountains, 9 (July 15-30, 1921, 

 two mites on wing, O. C. Duffner); Pinal Co., "14 miles east of Oracle," cf 

 (July 24, 1924, E. P. Van Duzee). Florida: Winter Park, cf (Sept. 1946, 

 A. B. Klots). Texas: Basin, Big Bend National Park, Brewster Co., cf (July 

 5, 1948, C. & P. Vaurie); locality and date unknown, 3 d' cf , 9 ("Tex.," 

 Andreas Bolter collection), cf ("Paratype," M. E. Murtfeldt collection, Cornell 

 University) . 



Remarks. — This species undoubtedly ranges southward into 

 Mexico, with the specimen from Florida considerably darker than 

 the others. A. cressoni is closely related to maculifer and crescentel- 

 lus, with which it forms a distinct species group. This group has 

 been characterized in the key and in the foregoing remarks on macu- 

 lifer. All three species may be distinguished from one another, and 

 from all other acrolophids treated here, on the basis of their harpes 

 and aedeagi. In cressoni, the aedeagus is curved strongly ventrad 

 and its base is expanded into a recurved process. The genital char- 

 acters are consistent throughout my rather small series of this species. 



Mr. Tams of the British Museum (Natural History) has sent 

 photographs labeled ^'cressoni Wals., type" showing the adult cf and 

 its genitalia. These photographs confirm the identity of this species. 



