Subspecies Papilio polyxenes asterius - Black Swallowtail
Butterflies of Pennsylvania, a field guideBy James L. Monroe, David M. Wright
University of Pittsburgh Press
From the publishers page:
This work has all of the features that make field guides to a region's butterfly fauna useful to anyone with a serious interest in that fauna. . . . the book is a bargain and a must for anyone with an interest not just in Pennsylvania's fauna, but the northeast fauna as a whole.
News of the Lepidopterists' Society
Winner, 2017 National Outdoor Book Award
Though I am in the southeast, I own this field guide and find it very useful - Roy Cohutta Brown.
A Swift Guide to Butterflies of North America: Second EditionBy Jeffrey Glassberg
Princeton University Press, 2017
This is a revised second edition of the most detailed, comprehensive, and user-friendly photographic field guide to the butterflies of North America. Written by Jeffrey Glassberg, the pioneering authority on the field identification of butterflies, the guide covers all known species, beautifully illustrating them with 3,500 large, gorgeous color photographs—the very best images available. This second edition includes more than 500 new photos and updated text, maps, and species names. For most species, there are photographs of topsides and undersides, males and females, and variants. All text is embedded in the photographs, allowing swift access in the field, and arrows point to field marks, showing you exactly what to look for. Detailed, same-page range maps include information about the number of broods in each area and where strays have been recorded. Color text boxes highlight information about habitat, caterpillar food plants, abundance and flight period, and other interesting facts. Also included are a quick visual index and a caterpillar food plant index. The result is an ideal field guide that will enable you to identify almost every butterfly you see.
Butterflies of Louisiana: A guide to identification and locationBy Marks, C.
LSU Press, Baton Rouge, LA, 2018
Craig Marks. 2018. Butterflies of Louisiana: A Guide to Identification and Location. LSU Press, Baton Rouge, LA. 472 pgs.
Butterflies abound in every region of the Bayou State, and with this authoritative resource in hand, both the experienced and novice butterfly watcher can identify a frequent backyard visitor or pinpoint the haunts of a particular species. With a long flight season stretching from late February to early November, Louisiana offers an abundance of opportunities to observe the 154 native species of butterflies, whose habitats range from coastal prairies to swampland to northern piney woods.
A Swift Guide to Butterflies of Mexico and Central America, Second Edition.By Glassberg, J.
Princeton University Press, Princeton, NJ. 304 pp., 2018
Glassberg, J. 2018. A Swift Guide to Butterflies of Mexico and Central America, Second Edition. Princeton University Press, Princeton, NJ. 304 pp.
3,250 color photos and maps
A groundbreaking photographic field guide to almost all of Mexico's butterfly species and many of Central America's
This is a revised second edition of a groundbreaking photographic field guide to the butterflies of Mexico and Central America. Written by Jeffrey Glassberg, the pioneering authority on the field identification of butterflies, the guide covers more than 2,000 species and features over 3,700 large, gorgeous color photographs, the very best images available, accompanied by authoritative facing-page text. This second edition includes more species, more than 1,500 new photos, and updated text, maps, and species names. And range maps, field marks, and host plants are included for all Mexican butterflies. The result is an ideal field guide that will enable you to identify almost every butterfly you see.