The Mayflies, or Ephemeroptera, of Illinois. B. D. Burks, 1975 reprint of Bulletin of the Illinois Natural History Survey, Vol. 26, 1953. Entomological Reprint Specialists, Los Angeles, California, viii + 216 p., 395 figs. $15.00.

(excerpt) The continuing demand for general references and aids to identification of Ephemeroptera has undoubtedly prompted the recent reprinting of The Mayflies. . . of Illinois. A two-page preface by George F. Edmunds, Jr. dealing with taxonomic and nomenclatural changes since the original 1953 publication has been added and will serve as an adequate aid to those unfamiliar with changing concepts in mayfly systematics. The reprinting is of high quality with the large number of figures having been excellently reproduced in this hard-bound edition

The Relationship Between North and Middle American \u3ci\u3eStenonema\u3c/i\u3e (Ephemeroptera: Heptageniidae)

Stenonema integrum (McDunnough) is shown to be a junior synonym of S. mexicanum (Ulmer.) n.syn. Subspecific status is delegated to Nearctic and Neotropical populations of this species as S. m. imegrum and S, m. mexicanum, respectively. Newly studied materials from Costa Rica and Belize indicate that adults of the two subspecies may be differentiated by the presence of thoracie pleural stripes in S. m. mexicanum. Consistent differentiating lanai characteristics are not known, A Pleistocene dispersal into Middle America and subsequent vicariance is hypothesized

New Larval Descriptions and Comparisons of North American \u3ci\u3eChoroterpes\u3c/i\u3e (Ephemeroptera: Leptophlebiidae)

Formal descriptions of larvae of the western North American species Choroterpes albiannulata and the eastern North American species Choroterpes fusca (Ephemeroptera: Leptophlebiidae) are given for the first time. Specimens, including reared adult and larval associations, of C. albiannulata were available from Nevada, Oregon, and Idaho, and rearings of C. fusca were made from the Huron Mountains in the Upper Peninsula of Michigan. Six of the nine species of North American Choroterpes (subgenus Choroterpes) are now known as larvae. Larval characteristics are compared, particularly with regard to similarities and differences between C. albiannulata and C. fusca, c. albiannulata and the western C. inornata. and C. fusca and the eastern C. basalis. Choroterpes albiannulata is distinct but shares gill morphology with C. inornata. Choroterpes fusca is quite similar to C. basalis, sharing . morphology and color patterning, but with some apparent differences that may prove to be consistent. Certain Choroterpes larvae from Arkansas are probably C. oklahomae (known only as adults from Oklahoma) but cannot be associated at this time. Distributions of species of subgenus Choroterpes are updated, and a revision of the entire genus based on cladistic analysis is recommended

A Natural Subgeneric Classification of \u3ci\u3eEphemerella Bartoni\u3c/i\u3e and Related Species (Ephemeroptera: Ephemerellidae)

Phyletic relationships indicate that Ephemerella bartoni Allen should be excluded from the subgenus Dannella in order to prevent a polyphyletic and impractical classifica- tion. A classification in the subgenus Eurylophella is more consistent with the species\u27 phyletic relationships

The Sand-Dwelling Predatory Mayfly \u3ci\u3ePseudiron Centralis\u3c/i\u3e in Michigan (Ephemeroptera: Pseudironidae)

(excerpt) An examination of samples of Ephemeroptera larvae taken from 19 sites on the Pere Marquette River, Mason County, Michigan in October, 1990 and May, 1991 by A. G. B. Primack (Indiana University, Bloomington) revealed the presence of Pseudiron centralis McDunnough. This species was taken at seven sites between State Highway M37 and Rainbow Rapids, east of Ludington

Commentary on \u3ci\u3eAmetropus\u3c/i\u3e Species (Ephemeroptera: Ametropodidae) in North America

Ametropus albrighti is shown to be a junior subjective synonym of A. neavei, n. syn. Ametropus neavei sensu lato demonstrates stable structural characteristics with respect to male genitalia and larval morphology, whereas degree of maculation and therefore abdominal patterning varies both among populations and within populations. Ametropus ammophilus is distinctive, and the two North American species are apparently allopatric based on known distributions, which are reviewed

Pre-Management Assessment of Aquatic Macroinvertebrates in a Small, Sedimentary Drainage Area of the Maumee and Lake Erie Basin

In order to establish baseline data adjunct to the research and development of soil conservation practices for sediment reduction in the Maumee River and Lake Erie, the aquatic macroinvertebrates of Black Creek and adjacent areas in northeastern Indiana were studied from 1974-1975. A total of 90 species of Insecta and Crustacea were taken, 69 from Black Creek. Species diversity indices ranged from 1.04 to 2.75 in two downstream locations and were generally reflective of stressed conditions related to channelization and sedimentation from the agrarian drainage area. Benthic species from the adjacent Maumee River potentially contribute in part to population maintenance in Black Creek

Discrete Tracy--Widom operators.

Integrable operators arise in random matrix theory, where they describe the asymptotic eigenvalue distribution of large self-adjoint random matrices from the generalized unitary ensembles. This paper considers discrete Tracy--Widom operators, and gives sufficient conditions for a discrete integrable operator to be the square of a Hankel matrix. Examples include the discrete Bessel kernel and kernels arising from the almost Mathieu equatio and the Fourier transform of Mathieu's equation