NORTH AMERICAN ACROLOPHIDAE — HASBROUCK 631 



broad ventral wall; apex slightly narrowed, deeply and usually asym- 

 metrically cleft. 



Vesica large, membranous, consisting of several infolded layers, 

 armed with single cornutus; cornutus large, elongate, rather slender, 

 heavily sclerotized, linear, directed distad, base weakly and irregularly 

 expanded, apex acute. 



Type, — Type cf in the Academy of Natural Sciences of Phila- 

 delphia. 



Type locality. — Not given by author, but presumably Phila- 

 delphia, Pa. 



Distribution. — Central and eastern United States. Nebraska and 

 Texas eastward to New Hampshire and Florida. 



Specimens examined. — 174, from 58 locahties. The large number 

 of specimens available for study has made it advisable to reduce the 

 distributional data for this common species largely to the localities and 

 months of occurrence: 



California: One cf , from the American Museum of Natural History, labeled 

 "Mariposa Grove, Calif., Aug. 11, 1916" (this record is very questionable). 

 Connecticut: East River (July); New Haven (June, July); Pleasant Valley 

 (Oct.); South Meriden (July). Florida: Biscayne Bay, Dade Co. (no date); 

 Coral Gables (June) ; Florida City (March) ; Miami (Dec.) ; Orlando (Aug.) ; 

 Royal Palm Park (Dec). Georgia: Clarke Co. (June); Pomona (June). 

 Illinois: Algonquin (June, July, Aug., at light); Champaign-Urbana (June, 

 July, Oct., both sexes common at light in June and July) ; Chicago (June) ; Edge- 

 brook (June, July) ; Homer Park, Homer (June) ; McHenry (June) ; Oregon 

 (July, at light) ; Palos Park (June and July, at light) ; Peoria (June, July, Sept., 

 at light); Putnam Co. (June, July); Quincy (May); River Grove (June). Indi- 

 ana: Hessville (June and July, 1 o" with mites on eyes). Iowa: Des Moines 

 (July). Kansas: Lawrence (June). Louisiana: Alexandria (June); Opelousas 

 (July). Massachusetts: Woods Hole (June). Missouri: Kirkwood (June); 

 St. Louis (June). Nebraska: Lincoln (July). New Hampshire: Hampton 

 (June, July). New Jersey: Ramsey (July, Aug.); Union Co. (July); Wenonah 

 (July). New York: Poughkeepsie (July); West Point (July). Long Island: 

 Orient (Aug.) ; Prospect Park (July) ; Richmond Hill (July) ; Riverhead (June, 

 Aug.). North Carolina: Brevard (July); Hendersonville (July); Weaverville 

 (Aug.). Ohio: Bellefontaine (July) ; Granville (July) ; Marion (July). Penn- 

 sylvania: Allegheny Co. (no date) ; Butler (July); "Clarksval." (July) ; Finley- 

 ville (June) ; Hunters Run (July) ; Oak Station, Allegheny Co. (June) ; Pittsburgh 

 (no date). Tennessee: Locality unknown, 2 9 9 (July 3, 1905, W. Osburn). 

 Texas: Richmond (Brazos River, June). 



Remarks. — One of the first three acrolophids described from the 

 United States, arcanellus is widely distributed throughout essentially 

 the same area in which plumifrontellus occurs. It is also fairly 

 common and somewhat variable in coloration. It is interesting to 

 note that arcanellus, despite its age, wide range, abundance, and 

 variability, has been described as new only once from America north 

 of Me.xico. 



676-573—64 10 



