1988] 
Wolfe — Hydrovatus methlini 
343 
Relationships among Laccornis, MethYmi-Hydrovatus, Canthy- 
porus, Laccornellus, and Lioporeus proposed by Wolfe (1985) are 
reviewed. Based on structural considerations only, Laccornis still is 
recognized as the sister to all other Hydroporinae, and the next 
most plesiotypic group is represented by a polychotomy of Canthy- 
porus, Laccornellus, and Methilini -Hydrovatus; however, the spe- 
cific relationships between the latter three clades cannot be as 
confidently predicted as previously thought. Members of Liopore- 
ous, Bidessini, Deronectes, Oreodytes, Hygrotus, Graptodytes, and 
Hydroporus sensu latu are relatively more apotypic than Canthypo- 
rus etc. Characteristics of the internal elytral ridge and mesotibial 
chaetotaxy suggest Lioporeus and Bidessini are more primitive than 
the latter five groups, but these latter relationships cannot be estab- 
lished conclusively. 
Acknowledgments 
I thank Dr. R. E. Roughley (University of Manitoba) for many 
hours of discussions and debate concerning dytiscid phylogeny; Dr. 
P. J. Spangler (National Museum of Natural History), Dr. D. 
Kavanaugh (California Academy of Science), C. H. S. Watts (South 
Australian Museum), and M. Bacchus (British Museum Natural 
History) for providing specimens critical to this study and Ms. Sule 
Oygur for assistance in manuscript preparation. 
This article is New Jersey Agricultural Experiment Station Publi- 
cation No. D-084 12-06-87, supported by state funds. 
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