SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 111, NUMBER 11 XTbomas Xincoln Case^ jFunb LARVAE OF THE ELATERID BEETLES OF THE TRIBE LEPTUROIDINI (COLEOPTERA: ELATERIDAE) BY ROBERT GLEN Research Coordinator, Division of Entomology, Science Service, Department of Agriculture, Ottawa, Canada (Publication 3987) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION APRIL 19, 1950 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 111, NUMBER 11 ^bomae Xincoln Case^ dfunb LARVAE OF THE ELATERID BEETLES OF THE TRIBE LEPTUROIDINI (COLEOPTERA: ELATERIDAE) BY ROBERT GLEN Research Coordinator, Division of Entomology, Science Service, Department of Agricultur Ottawa, Canada (Publication 3987) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION APRIL 19, 1950 BALTIMORE, MD., U. 8. A. CONTENTS Page Introduction i Acknowledgments 2 Literature 4 Methods and procedure 9 Rearing g Preservation and storage of material 10 Preparation of material for examination 10 Examination of material 11 The reconnaissance survey 11 The detailed study 11 Abbreviations used in illustrations 13 Listing the material examined 17 Morphology of a typical lepturoidine larva 18 Terminology 18 Morphology of the mature larva of Ludius acripennis destructor Brown. 19 Keys and descriptions 29 Larval characteristics of the family Elateridae (with key to subfamilies). 32 Larval characteristics of the tribe Lepturoidini (with key to genera) ... 33 Genus Ludius Eschscholtz (with key to species groups) 35 The Ludius aeripennis group 41 Ludius aeripennis (Kirby) 42 Ludius appropinquans (Randall) (?) 44 Ludius priwiimis (Horn) 45 Ludius aeneus (Linnaeus) 46 Ludius latus (Fabricius) 48 The Ludius inflatus group 49 Ludius glaucus (Germar) 50 Ludius inflatus ( Say) (?) 55 The Ludius edzuardsi group 56 Ludius sexualis Brown (?) 57 Ludius cruciatus fcstimis (LeConte) (?) 62 Ludius spretus ( Mannerheim ) 63 Ludius melancholicus (Fabricius) 64 Ludius amplicollis (Germar) 64 The Ludius semivittatus group 65 Ludius semivittatus ( Say) (?) 66 The Ludius propola group 67 Ludius propola propola (LeConte) 68 Ludius hieroglyphicus ( Say) 73 Ludius pudicus Brown 74 The Ludius triundulatus group 75 Ludius tri^mdnIatHS (Randall) 76 Ludius nebraskensis (Bland) (?) 81 iii CONTENTS Page The Ltidms fallax group 82 Ludius tessellatus (Linnaeus) 84 Ludins castaneus (Linnaeus) 89 Ludius viduus Brown (?) 9° Ludius bombycinus (Germar) 91 Ludius mediamis (Germar) 92 Ludius purpnreus ( Poda) 93 Ludius affinis (PaykuU) 93 The Ludius rotundicollis group 94 Ludius rotundicollis (Say) 96 Ludius sulcicollis ( Say) 102 Ludius ductus ( PaykuU) 104 Ludius bipustulatus (Linnaeus) 106 The Ludius nitidulus group in Ludius nitidulus (LeConte) 1 12 Ludius rujoplcuralis Fall (?) 117 Ludius nigricorms (Panzer) (?) 1 18 Ludius divaricatus (LeConte) 118 The Ludius cupreus group 124 Ludius cupreus (Fabricius) 126 Ludius pectinicornis (Linnaeus) 131 Ludius virens (Schrank) I33 Ludius kendalli (Kirby) I34 Ludius appressiis (Randall) 135 Ludius resplcndens aerarius (Randall) 136 Ludius sjaelandicus (Miiller) 142 The Ludius pyrrhos group 147 Ludius pyrrhos (Herbst) 148 Ludius protractus (LeConte) I49 The Ludius limoniijormis group 150 Ludius liinoniiformis (Horn) (?) 151 Ludius cylindriformis (Herbst) (?) 156 Genus Limonius Eschscholtz 157 The Limonius aenconiger group I59 Limonius pilosus (Leske) (?) 160 Limonius pectoralis LeConte 161 Limonius confusus LeConte (?) 162 Limonius aeger LeConte 163 The Limonius canus group 164 Genus Elathous Reitter 167 Elathous bicolor (LeConte) 167 Genus Leptiiroides Herbst 168 Genus Athous Eschscholtz 170 The Athous vittatus group 171 The Athous rufifrons group 173 Athous mutilatus Rosenhauer 174 The Athous cucullatus group 175 The Athous undtilatiis group 177 Genus Hemicrepidius Germar 178 Genus Crepidomenus Erichson 181 Crepidomenus qucenslandicus Blair 181 CONTENTS V Page Genus Crypt ohypnus Eschscholtz 183 The Cryptohypmis riparius group 184 Cryptohypnns junebris Candeze 185 Cryptohypmis abbreviatus (Say) 185 Genus Hypnoidtis Stephens 186 Genus Eanus LeConte 187 Genus Melaimctes LeConte 189 Melanactcs densus LeConte 189 Summary of taxonomic relationships 190 Diagram of general relationships between lepturoidine genera and "species groups" of Ludius 191 The genus Ludhis 192 The Athoiis complex 194 The genus Limonius 195 The genera Hypnoidtis and Cryptohypmis 195 The tribe Lepturoidini 196 List of species studied 196 Literature cited 199 Figures i to 40 207 tE^llomas Hincoln Caficp Jfunb LARVAE OF THE ELATERID BEETLES OF THE TRIBE LEPTUROIDINI (COLEOPTERA: ELATERIDAE) By ROBERT GLEN i Research Coordinator, Division of Entomology, Science Service, Department of Agriculture, Ottazva, Canada INTRODUCTION Characters for the identification of species are sadly lacking for most of the larval Elateridae. This lack of fundamental information is not surprising because most elaterid larvae are difficult to find and they require several years to mature. The task of collecting and rearing them is so great that only a small proportion of the specie§ is known in the larval stage, and progress in larval taxonomy has been handicapped constantly by insufficient representation to charac- terize the genera. This is particularly true of the Lepturoidini, which includes important crop pests throughout the world, especially in western North America. Many of these pest species are now known to react differentially to factors of weather, soil, and culture, and the control program to be prescribed depends largely upon the species involved. Thus, accurate specific identification is the first need of the economic investigator. It was largely to fill such a need that the present study arose. In 1922 K. M. King, Officer in Charge of the Dominion Entomo- logical Laboratory, Saskatoon, Saskatchewan, initiated investigations upon wireworm control in the Prairie Provinces, and as an integral part of the project he included studies of larval morphology. He continued this work, as time permitted, until 1929 and succeeded in rearing several of the pest species and in obtaining characters for the separation of their larvae in the field. The author was then made responsible for the furtherance of this work, and in 193 1 he prepared descriptions of the larvae of 18 Saskatchewan species. This experi- 1 Formerly in charge Wireworm Investigations, Dominion Entomological Laboratory, Saskatoon, Saskatchewan. SMITHSOMIAN MISCELLANEOUS COLLECTIONS, VOL. Ill, NO. 11 2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill dice, together with a study of the Uterature, convinced the writer that adequate generic and specific characters could not be drawn from an investigation Hmited to the Elateridae of Saskatchewan, or from super- ficial studies covering a larger region. Instead, he concluded that true generic and specific characters could be obtained only through an in- tensive comparative study involving all available species of the group under investigation. The present study, which deals particularly with the genus Ludiiis Eschscholtz, is based upon these principles. In the broad sense it consists of two parts : a detailed treatment of all available identified Ludiiis larvae in the world, and a comprehensive survey of the larval morphology of the other genera included by Hyslop (1917) in the tribe Lepturoidini. The investigation was discontinued in 1942 and is believed to be a reasonably complete record and analysis of the perti- nent information available at that time. Only mature or nearly ma- ture larvae are considered. The 93 species included represent 11 genera as follows: Athons (14), Crepidomemis (i), Cryptohypnus (5), Eanus (2), Elathous (i), Hemicrepidius (5), Hypnoidus (3), Lepturoides (3), Linionhis (14), Ludius (44), and Melanactes (i). It is essentially a study in detail and will be used most conveniently by workers who have a knowledge of the basic morphology of ela- terid larvae as outlined by Glen, King, and Arnason (1943). ACKNOWLEDGMENTS By far the greater part of this study was conducted at the Dominion Entomological Laboratory, Saskatoon, Saskatchewan. However, more than 6 months' intensive research was done in 1936-37 at the United States National Museum, Washington, D. C, and considerable time was devoted to this project at the University of Minnesota, INIinne- apolis, Minn., where the writer was privileged to work under a Caleb Dorr Fellowship for 1931-32 and a Shevlin Fellowship for 1932-33. With deep appreciation the writer acknowledges his indebtedness to these institutions and to the many friends and associates who have given stimulating and helpful advice throughout the study. Special acknowledgment of assistance is due Dr. Kenneth M. King, formerly in charge of the Saskatoon laboratory, who contributed so much to the viewpoint, the plan, and the methods adopted, and with whom constant consultation has been a valuable privilege ; Dr. A. G. Boving, formerly senior entomologist, United States Bureau of Entomology and Plant Quarantine, Washington, D. C., whose counsel and gui- dance have been of lasting benefit ; Dr. C. E. Mickel, Professor of :; II NO. LARVAE OF THE ELATERID BEETLES GLEN 3 Entomology, University of Minnesota, for assistance in planning and developing the study; W. J. Brown, Ottawa, Canada, for the iden- tification of all reared adults made available to the writer and for assistance with nomenclatorial and taxonomic difficulties ; M. C. Lane, Walla Walla, Wash., for the identification of reared adults in his possession and for his cooperation in obtaining larval material ; and H. G. Crawford,