GENERA OF AMERICAN CICADAS NORTH OF MEXICO By MAXINE SHOEMAKER HEATH A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY CF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA .1978 To my family , Jim, Cindy, Pam, Jessica ACKNOWLEDGEMENTS Many people have generously contributed time, advice, and information useful in the preparation of this dissertation. I would like to thank Dr. Thomas Moore of the University of Michigan, Dr. George Byers, Dr. Peter Ashlock, and Dr. Charles Michner of the University of Kansas, Dr. Frank Hasbrouck and Mr. Martin Kolner of Arizona State University, Dr. and Mme. Michel Boulard of the Museum National d'Histoire Naturelle, Dr. T. Knight and Dr. Peter Broomfield of the British Museum (Natural History), Mr. Donald Webb of the Illinois Natural History Survey, Dr. Frank Mead of the Florida Division of Plant Industry, and Dr. Jack Cranford of Virginia Polytechnic Institute for their interest, information, access to col- lections, and loans and gifts of cicada specimens. Mrs. Alice Prickett assisted me in the planning of the illustrations. I thank my committee, Professors Reece Sailer, Harvey Cromroy, Lewis Berner, Ellis Matneny, and Frederick King, for continued advice and encouragement. Most of all I would like to thank my family for assistance and sacrifices, especially my husband, James E. Heath, who introduced me to the study of cicadas, and whose continued help and encouragement made this dissertation possible. TABLE OF CONTENTS Page ACKNOWLEDGEMENTS iii ABSTRACT viii CHAPTER I INTRODUCTION I Life Cycle 4 The Problem 7 II MATERIALS AND METHODS 9 III CLASSIFICATION: HIGHER TAKA 11 Order 11 Suborder 11 Superfamily 11 Family Cicadidae 12 Subfamilies 20 Tribes 22 IV CLASSIFICATION: GENERA 26 V GENERAL MORPHOLOGY 29 General Body Proportions 32 Head . . . 32 Thorax 39 Legs 42 Wings 42 Abdomen 43 Sexual Characteristics 51 Internal Structure Revealed by Radiographs 52 VI KEYS TO GENERA 61 Males 61 Females 63 VII BeamevLa 65 Taxonomy 65 Description 66 Page Distribution 70 Discussion 70 VIII Caaama 71 Taxonomy 71 Description 72 Distribution 76 Discussion 76 IX Ciaadetta 79 Taxonomy 79 Description SI Distribution 36 Discussion 87 X Clidophleps 39 Taxonomy 89 Description 90 Distribution 94 Discussion 95 XI Comuplura 97 Taxonomy 97 Description 98 Distribution 102 Discussion 102 XII Dioevoprccta 104 Taxonomy 104 Description 105 Distribution 110 Discussion Ill XIII Magiaicada 114 Taxonomy 114 Description 115 Distribution 119 Discussion 120 XIV Neooiaada 125 Taxonomy 125 Description 126 Distribution 131 Discussion 131 Page XV Neoplatypedia 134 Taxonomy 134 Description 135 Distribution 137 Discussion 140 XVI Okanagana 142 Taxonomy 142 Description 144 Distribution 149 Discussion 149 XVII Okanagodes 152 Taxonomy 152 Description 153 Distribution 157 Discussion 157 XVIII Pacavina 159 Taxonomy 159 Description 159 Distribution 164 Discussion 164 XIX Platupedia 165 Taxonomy 165 Description 166 Distribution 172 Discussion 172 XX Quesada 176 Taxonomy 176 Description 177 Distribution 181 Discussion 181 XXI Tibioen 133 Taxonomy 183 Description 186 Distribution 190 Discussion 192 XXII Tibxainaides 195 Taxonomy 195 Description , 196 Distribution Discussion . Page 200 200 XXIII DISCUSSION AND CONCLUSIONS 202 Origins and Dispersal 202 Ecology and Distribution 207 Evolution of Higher Taxa ^0" Evolution and Morphology 210 Summary 2x7 LITERATURE CITED. BIOGRAPHICAL SKETCH 219 231 Abstract of Dissertation Presented to the Graduate Council >f the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy GENERA OF AMERICAN CICADAS NORTH OF MEXICO By Maxine Shoemaker Heath August, 1978 Chairman: Reece I. Sailer Co-chairman: Harvey L. Cromroy Major Department: Entomology and Nematology Cicadas are large, vocal insects, often heard, but seldom seen. Sixteen endemic genera occur in the Nearctic biogeographic region north of Mexico. The genera are Beameria, Caoama, Cioadetia, Clidovhleps, Cornuplura, Dioevopvoota, Magioioada, Neoaicada, Necplatypedia, Qkanagana, Okanagodes, Paoarina, Platypedia, Quesada, Tibioen, and Tibioinoides. Each of these genera is redescribed in a consistent format, thereby facilitating comparisons of common characters. Keys to males and females are included, and diagnostic characters are given for each genus. Radiographs, made with soft x-rays, are used as a taxonomic technique to elucidate internal structures. The following revisions are recognized: Qkanagana -{"Xbr>ooaudata, a former variety of Q. bella is raised to species rank; Ckanagana rotundifrons is transferred to the genus Clidovhleps; Tibioinoides hesper-ia is moved back to Okanagana; Cioada ohisos is placed in the genus lleooioad.a. A new tribe, Okanaganini, is proposed for six western genera with the possibility of including two palearctic genera. This tribe has two sub tribes, Platypedaria and Okanaganaria. The cicada fauna in North America is old. Earliest fossils date from the Paleocene. Current distribution is dependent on origin, dispersal patterns, habitat, and past geologic history. Two major radiations of genera have occurred on the North American continent, one allied to Tibiaen, the other to Okanagana. Ancestral and derived characters are proposed and related to the North American genera. CHAPTER I INTRODUCTION Cicadas undoubtedly intrigued the imagination of man before recorded history. A frequently related ancient observation noted how lucky the male cicada is because his mate is mute. The following pages will show that even among cicadas some females have managed to develop a "voice." Myers (1929), in his book Insect Singers, reviewed both the classical and modern literature, summarizing what was known about cicada biology at that time. The first written references to cicadas, "tettix" in Greek, can be found in those sections of the Iliad attributed to Homer and written around 1,000 B.C. Another poet from the same era, Hesiod, noted that the sound comes from beneath the wings, an observation made and lost many times before sound production organs in cicadas were identified and de- scribed. The ancient Greeks apparently found the song of the cicada pleasing and musical. In Greek mythology, cicadas were formerly men who were so enchanted when the Muses brought music to the earth that they became absorbed by the music, neglected to eat and sleep, and eventually wasted away. Their voices may still be heard in the singing of cicadas. In contrast the ancient Romans found the sound of the cicada unpleasant and raucous. Roman mythology tells of the goddess Aurora, who fell in love with a mortal. She asked the gods to grant her lover the gift of immortality, but in her enthusiasm she neglected to ask for eternal youth -1- -2- for him. As the years passed Tithonus, her lover, became toothless and infirm and prayed for death. However, the gift of the gods could not be returned, so Aurora changed her toothless lover into "the ever complaining cicada." I prefer to think that these differences in the perception of cicada song relate to a taxonomic difference in cicadas rather than a difference in aural perception of ancient Greeks and Romans. From the fables of Aesop, the stories of ancient India, and the folk- lore of the Maori tribes of New Zealand come amazingly similar tales contrasting the industrious ant at the foot of a tree with the lazy cicada singing in the sun at the top of its crown. When winter came the ant was well fed and survived, while the cicada begged for food and eventually starved. The Zuni Indians of the American Soucwest attribute more cunning to the cicada. They tell the tale of a coyote who wished to learn the song of a cicada singing from the boughs of a pinyon pine. The coyote had difficulty learning the song and twice forgot it on the way home. When he returned for the second time, the cicada, distrustful of the coyote, divested himself of his old skin, filled it with a quartz pebble, sealed the vent with pitch, and flew to the safety of another tree. The coyote became frustrated when this cicada image did not respond, siezed it and splintered his teeth on the stone, driving some into his jaw and leaving others protruding as tusks. His descendants inherited these broken teeth. The cicada of the pinyon pine is either Tibi-ocn duvyi. or Okanagana magnified. In the Orient cicada symbolism was de- veloped to its greatest heights by the Taoists. They believe that the soul of the departed escapes the body and is carried aloft by a cicada. Early burials often included a cicada-shaped image, while in later burials a cicada amulet was placed in the mouth of the corpse to facili- tate the soul leaving the body. As the centers of western civilization moved northward to areas where cicadas are less prevalent, literary allusions to cicadas became scarcer. Keats and Browning mentioned them in their poetry, but they had lived in the southern Mediterranean regions of Europe. In the United States nearly all cultural allusions to cicadas center around the genus Magioiaada, misnamed "seventeen-year locusts" because their periodical abundance reminded early colonists of the biblical locusts. The earliest scientific work on cicadas was that of Aristotle. He described the morphology of the cicada mouth, their reproductive behavior, and life history. Taxonomically , he made the distinction between the large ones that sing and the smaller ones that do not sing. This latter observation probably descriminated between our modern family Cicadidae and other auchenorryncous Homoptera, although we now know many of these produce sounds that are seldom audible to the human ear. Although Aristotle was often quoted, cicada biology remained essentially in sus- pended animation until Reamur described the sound producing organs and made observations on the nests and eggs in the eighteenth century. Linnaeus established the genus Cicada in 1758 in Systemma Naturae. In the nineteenth century Fabre recorded the habits of some Mediterranean Cicadidae. Since that time numerous other writers have described species and various aspects of cicada morphology and biology. These are sum- marized by Myers (1929). Distant, in a series of papers entitled Rhynochotal Notes appearing in the Annals and Magazine of Natural History (1904-1905), established our current system of cicada taxonomy. The earliest attempt to treat the classification of North American cicadas comprehensively was Uhler's Preliminary Survey of the Cicadaea of the United States, Antilles, and Mexico, published in two parts in -4- Entomologica Americana in 1888. Van Duzee published a checklist of genera and species occurring north of Mexico in 1916 and followed this with a catalog of the same genera and species the subsequent year. Davis treated the distribution of the genera and species in 1930. Metcalf's (1963) world catalog is the most recent work to treat North American genera comprehensively. Other papers dealing with several North American genera are Lawson (1920), Beamer (1928), Beamer and Beamer (1930), Froeschner (1952), Simons (1953, 1954), Moore (1966), and Alexan- der, Pace, and Otte (1972). The writers primarily concerned with each genus are reviewed under the individual genera in the following chapters. William T. Davis made the most significant contributions to our knowledge of western North American Cicadidae. For Davis the study of cicadas was a second vocation. What began as a hobby during his years as a successful industrialist became, after an early retirement, his primary preoccupation until his death in 1944. Davis described many of our genera and species. He was dependent for most of his specimens on the collections of other people, but in his writings he included whatever biological information was sent to him in letters accompanying the specimens. Since Davis1 death most work in North America has centered around the periodical cicadas of the genus Magiciaada. Life Cycle Cicada eggs are laid in nests along the stems and branches of various host plants. The nests may or may not be arranged in a definite order. The female pierces the host with the ovipositor gradually driving into the host tissue with an in-and-out sawing motion of the lateral valves. Some species simply lay the eggs in the dry nest. Other species fill the ■5- ends of the nest or the entire nest with a glue-like secretion, and some, e.g., Tibioen lyviaen, press the torn tissues of the plant back into place before moving on to the next nest. Beamer (1928) recorded from as few as three to as many as twenty eggs in the nests of Kansas Cicadidae, while Myers (1929) cited estimates of egg production for a single female that range from three hundred to seven hundred. All de- scribed eggs resemble each other closely in structure, varying only in size. Some species overwinter as eggs. The eggs of other species hatch the same summer they are deposited. The hatching embryo ruptures the anterior end of the egg capsule with its egg burster and makes its way to the nest opening, where it sheds the postnatal membrane and falls to the ground. Upon reaching the ground, the young nymph searches for a crevice in the earth to enter. A quick retreat underground is especially important in dry habitats as the newly hatched nymphs appear to be particularly vulnerable to desiccation. Once in the ground, the nymph continues its downward movement until it locates a suitable spot for a cell. The cell apparently is constructed before food is located (Beamer, 1928). The cell protects the nymphal cicada from both flooding and desiccation and probably provides some protection from predators. The cell consists of walls of hard packed earth. It is cylindrical and large enough to permit the nymph to do a half somersault, his method of turning around. Once the cell is built, the nymph looks for food. If food lies at the edge of the cell, he begins to eat. If there is no food on the periphery of the cell, he searches for food by laboriously moving his cell with him. Digging and packing of the earth is done with special adaptations of the prothoracic -6- legs. Much of the above was verified by Beamer (1928) from observations made on cicada nymphs in glass-sided cages. Like most Homoptera, cicadas have five nymphal instars. The shortest life cycle known is four years, a fact established by Beamer (1928) for Cioadetta calliope. The longest cycle is the seventeen year cycle of three species of Magiaicada. In the last month before emergence, the fifth nymphal ins tar extends its cell to within an inch or two of the surface. J.E. Heath (1968) showed that emergence from the ground of seventeen-year cicadas is dependent on soil temperature. Temperature is probably the environmental cue for emergence of other cicadas also. Upon emergence the nymph climbs a nearby stem or trunk before the final molt to an adult. The primary function of the adult stage is mating and renewal of the life cycle. Adult cicadas live approximately six weeks to two months. In some species, females appear to outlive the males by several days. The two sexes are attracted to each other by a mating call or song usually performed by the male. In Magiaicada the song appears to have a congregating function, bringing together both males and females rather than uniting specific pairs. In Flatypedia and Neoplatypedia both sexes signal in a two-way communication. Several species produce three dif- ferent sounds: the mating call, a sound used during courtship and mating of specific pairs, and an alarm squawk emitted by males when they are disturbed. Wing fluttering is also used as a signaling device between individual cicadas. After mating, the female lays her eggs and the cycle begins again. The Problem In June, 1968, J.E. Heath, P.J. Wilkin, and I began a study of the adaptations to climate of cicadas in Arizona. When we tried to identify our experimental animals, we became frustrated by the lack of taxonomic keys. No key to the genera of North American cicadas existed. Published descriptions of genera were often vague and incomplete. There was usually no way of comparing similar characters in one genus with another. Many of the descriptions were of a comparative nature, but they required identified specimens of the other genus or genera in hand in order to make the comparisons. In some cases a lone female was unidentifiable because only male diagnostic characters had been used. We were faced with two alternatives. We could compile a list and original descriptions of all species previously reported from the general region and hope that what we had collected was not a range extension or a new species, or we could travel to a large museum collection, and hope that our species were available for comparative identifications. In either case we would be working backward from species to genus or from a larger group to a smaller group. Everyone wishing to identify indi- vidual cicada specimens to genus could hardly follow these procedures. Clearly a comprehensive taxonomic study of the genera of American cicadas north of Mexico was needed. This paper presents such a study. The aims of this dissertation are 1. To provide thorough, consistent descriptions of adults of the genera of cicadas occurring in North America north of Mexico. 2. To provide keys and diagnostic characters for identification of individual specimens to genus. 3. To indicate the general distribution of North American genera north of Mexico. 4. To summarize the known biology of cicada genera found north of Mexico . 5. To indicate evolutionary relationships of the North American genera north of Mexico. CHAPTER II MATERIALS AND METHODS The personal collection of cicadas used in this study dates from 1964. Most of the specimens were collected under the auspices of the University of Illinois and arrangements have been made to deposit these, specimens in the Illinois Natural History Survey collection. Several broods of Mag-ioicada are included in the collection. Extensive col- lections of western genera were made in Arizona in June and early July of 1968, 1969, 1970, 1972, and 1973. Additional specimens were collected in Colorado, Illinois, and Florida. Notes were made on location, time of day, and habitat of each collection. Live weights and temperature data were frequently recorded. Specimens were preserved in alcohol and pinned and examined at a later date. Several museum collections were examined in part or whole. These included the Museum of Zoology, University of Michigan, Ann Arbor; Arizona State University, Tempe; Illinois Natural History Survey, Urbana; the Snow Collection, University of Kansas, Lawrence; the 3ritish Museum (Natural History), London; and the Museum National d'Histoire Naturelle, Paris. Numerous friends and colleagues contributed both specimens and collection data. Measurements were made using the following tools; a Wild M5 stereo- scopic dissecting microscope, calipers, and a plastic rule read easily to the nearest half millimeter. Measurements were made from both -10- specimens and photographs. The photographic plates found in the col- lected works of Davis (1921a, 1942) as well as my personal photographs were utilized for proportional measurements. Descriptions were written using the stereoscopic microscope and notes made while using the facili- ties of the museums visited. Radiographs were made with a Faxitron 804 field emission x-ray unit and Polaroid positive-negative 55 film. Details of exposure are given in the general morphology chapter. Additional prints and enlargements were made by the photographic services of the University of Florida. Illustrations were drawn with a camera lucida. Original sketches were compared with the descriptions and later reduced on a reducing Xerox prior to the final inking. Three illustrations were made directly from enlarged photographs. Color patterns are indicated, but the decision was made to leave black insects uncolored so that morphological features would not be obscured by the color. Several excellent drawings of male external genitalic segments are found in the literature. Some of these were redrawn from the originals after a comparison was made with specimens in hand. Unless otherwise indicated in the text, the terminology used in this paper conforms with that found in Torre-Bueno, A Glossary of Entomology, 1962. CHAPTER III CLASSIFICATION: HIGHER TAXA Order Cicadas are usually placed in the order Homoptera. This order is comprised of hemipteroid insects with a sucking beak arising from the back of the head. The proboscis contains four piercing stylets consisting of two mandibles and two maxillae. In winged members, the forewings are usually of a uniform texture throughout, either membranous or slightly thickened. The hind wings are membranous. Winged forms hold the wings tentlike over the body when at rest. Members of this order are plant feeders. Suborder Cicadas belong to the suborder Auchenorrhyncha . Insects in this suborder have three-segmented tarsi and short, bristle-like antennae. The beak arises from the back of the head and not between the fore coxae as in the Sternorrhyncha. Members of the Auchenorrhyncha are described as active insects. Cicadas are classified in the superfamily Cicadoidea. The designa- tion Cicadoidea, however, means different things to different authors. -11- -12- Those writers who divide cicadas into two or more families (cf. Kato, Boulard, and Metcalf) define the Cicadoidea as those insects comprising the former family Cicadidae. Authors who still maintain the single family Cicadidae as representing all cicadas use the designation Cicadoidea to separate the families Cicadellidae, Cercopidae, Membracidae, and Cicadidae from the Fulgoroidea. This definition of the Cicadoidea is characterized by antennae which arise on the front of the head between or anterior to the eyes; middle coxae short and contiguous; and no "Y" vein in the anal area of the wing (Borror and DeLong, 1971, and Borror and White, 1970). Family Cicadidae History Lamarck (1801) described the genus Cicada and named Cicada ovni Linn, as the type, thereby establishing the validity of the genus. Essig (1942) gave the following history of the family: "Latrielle grouped these in- sects as Cicadariae in 1802, and Leach erected the tribe Cicadides and the family Cicadida in 1815. The later was changed to Cicadidae by Samouelle in 1819 and has been generally accepted for this homogeneous group of remarkable insects." Westwood (1840) and Metcalf (1963) attrib- uted the name to Leach, but Leach's description of the tribe Cicadides reads, "Antennae three-jointed. Ocelli two. Tarsi with three joints" (Leach, 1832, First American edition, after Leach, 1815). This description specifically excludes the genus Cicada as established by Lamarck. Lamarck's genus falls under Leach's tribe Tettigonides. Leach's family Cicadida also excludes Lamarck's genus Cicada. Samouelle's (1819) work follows the classification of Leach. According to Article lOe and -13- Article 63 of the "International Code of Zoological Nomenclature" (1961) , a family name must be based on a valid generic name. Latreille's (1802) "Cicadariae" was roughly equivalent to Linnaeus' genus Cicada. It in- cluded two subgroups, "Cicadae verae" and "Cicadellae. " The genus Cicada made up the "Cicadae verae." There were five genera in the "Cicadellae." I believe this example is equivalent to the example given for Tipulidae on page 11 of the 1961 International Code of Zoological Nomenclature and the family Cicadidae, therefore, should be attributed to Latreille. Westwood (1840) was the first author to limit the term "Cicadidae" to this family of homopterous insects as we now recognize it. He equated Cicadidae to "Cicadae maniferae" of Linnaeus, the "Chanteuses" of Latreille, and the "Stridulantia" of Burmeister. Distant (1912), Myers (1929), and Kato (1961) gave credit to Westwood for establishing the family. Metcalf omitted Westwood from his "Bibliography of the Cicadoidea" (1962) . Westwood followed his designation by a detailed description of the family. Other descriptions I consulted were Amyot and Serville (1843) , Ashmead (1888), Edwards (1896), Distant (1912), Lawson (1920), Metcalf (1951 — cohors Cicadida) , Kato (1961 — superf amily Cicadoidea) , and Borrer and DeLong (1971). Characteristics The head is short and broad with an enlarged, cross-striated clypeus. Antennae are short and setaceous, arising between the eyes and beneath the supraantennal plates. There are three ocelli arranged triangularly on the epicranium. The head terminates beneath in an elongated, three- jointed rostrum. -14- The thorax is large and broad. The pronotura is short except in Tettigareta where it covers most of the mesonotum. There are two diagonal grooves on each side of the pronotum. The mesonotum is large and ter- minates in a raised X or cruciform elevation ("in Tett'igavota forming a scutellum," Kato, 1961). The metanotum is short and in some genera only visible laterally. Ventrally the thoracic segments are subequal. The abdomen consists of eleven segments. The first two are united ventrally and the ninth and tenth segments form the external genitalia. The eleventh segment bears the anal style. The third to seventh spiracles are in the sternites and not the pleura. The anterior femora are enlarged and spinose in all the genera of North America north of Mexico. Tibiae are slender and subcylindrical . There are no pulvilli or empodia between the tarsal claws. The meta- thoracic mera are well developed and extend posteriorly. The legs are not adapted for jumping, as in other auchenorrynchous Homoptera. Wings may be hyaline, opaque, or both. Venation is distinct. An ambient vein encloses the marginal cells. Forewings contain a basal cell. A nodal line running from the nodus of the costal margin to the anal margin may be indicated by auxiliary bumps and breaks in the venation. Wings are coupled in flight by a recurved flange on the dorsal surface of the costal border of the hind wing which hooks with a similar flange on the ventral surface of the anal border of the forewing. The ninth segment in both sexes is the pygofer, a more or less cylindrical, strongly chitinized case surrounding the genitalia. The aedeagus is further protected by a projection of the tenth segment known as the uncus. The shape of the uncus has been used as the basis for species determination in many species of North American Cicadidae. The -15- female external genitalia consist of three pairs of appendages making up the ovipositor and its sheaths. The central pair is fused distally. The apices of the middle pair are highly chitinized and possess cutting teeth or edges. The outer pair forms the sheath. Because methods of sound production among cicadas vary, the following sound "producing" structures cannot be considered characteristic of the entire family. Sound production has been so closely linked with cicadas, however, that a description of the family would not be complete without some mention of the most common structures associated with sound produc- tion and reception. Sounds are most commonly produced by the contraction and expansion of a tymbal organ located lateral to the first abdominal segment of the males. The tymbals may be either partially or totally covered from above by a forward projection of the second abdominal ter- gite or by a posterior projection of the mesonotum (Boulard, 1976a) . Males with functional tymbal organs usually possess posterior metastarnal projections called opercula. The hearing or chordotonal organ is located in the second abdominal segment. It may be indicated externally by a lateral bulge on the sternite. Many cicadas have accessory scridulating mechanisms and some produce sound by beating their wings together or against the substrate on which they are sitting. Current Taxonomic Status of the Family At least three authors use the superfamilial name Cicadoidea to encompass up to five families of cicadas. All of these divisions are based on sound production -echanisms and/or the coverings associated with them. -16- Kato (1961) lists four families. The two families Cicadidae and Tettigadidae have tymbal organs. The Tettigadidae have an accessory stridulating organ. The two families Platypediidae and Tettigarctidae lack a functional tymbal organ. Platypediidae produce clicking sounds with the forewings and have a chordotonal mirror. Tettigarctidae lack the usual chordotonal mirror. Metcalf (1951, 1963) lists two families of cicadas, Cicadidae and Tibicinidae. Cicadidae possess an anterior projection of the second abdominal tergite covering or partially covering the tymbal organ. Tibicinidae lack this projection. Boulard (1976a) divides cicadas into five families. The Tettigarc- tidae are separated out by their very long pronotum covering most of the mesonotum. Platypediidae lack a functional tymbal organ. A new family, Plautillidae, is characterized by tymbal coverings emanating from the metanotum and a reduction of the vannal region of the wings. Cicadidae and Tibicinidae include the remaining genera, with Cicadidae possessing an anterior projection of the second abdominal tergite in the males and Tibicinidae lacking such a projection. A definite difference exists in the philosophy and usefulness of the family taxon between those who place cicadas in a single family, Cicadidae, and the above three authors. If we accept Smith's definition of family as reiterated by Torre-Bueno (1962), we can analyze the above divisions: Family, a division or classification including a number of genera agreeing in one or a set of characters and so closely related that they are apparently descended from one stem. Fossil evidence is sparse, but modern characteristics seem to in- dicate that cicadas evolved from one stem. Almost all authors working -17- in cicada systematics eventually point out the basic similarity of all cicadas and bemoan the lack of truly separable characters. Most mor- phological characteristics of cicadas represent a continuum rather than a "have" or "have not" status. Some authors have attempted to explain this basic similarity on the basis of a homogeneous, long, subterranean life shared by the nymphal forms. To me this explanation seems fallacious, as edaphic characteristics of soil and differences in root characteristics of host plants can surely be as varied as the external environment of the imagos. The long life of the nymphs has resulted, however, in fewer generations of cicadas responding to evolutionary pressures than those insects with one or more generation per year. In North America north of Mexico, the shortest confirmed life cycle is the four year cycle of Cicadetta calliope (Beamer, 1928). The long life cycle could be a con- tributing factor to the lack of diversity in cicadan morphology. It seems evident, therefore, that the basic similarity of all cicadas verifies their descent from a single phylogenetic stem. The family Tettigarctidae used by both Kato and Boulard consists of one genus. Members of this genus are generally considered the most primitive of living cicadas. Although Tettigarata apparently differs considerably from other cicadas, separation of a single genus from its nearest relatives obscures that relationship. A subfamilial ranking seems more logical. Boulard (1975a, 1976a), himself, recognized that the family Platy- pediidae is not a natural grouping. The loss of the tymbal organ has occurred at least three times, in North America, in Africa, and in China. In both the African and North American genera, other characteristics relate them more closely to other genera in their respective geographical -18- areas than to each other. Platypedia and Neovlatypedia have several characteristics in common with the okanaganoid genera and would be better placed as a subdivision of the same taxa in which these genera are placed. The family as delineated by Kato and Boulard is characterized by a single negative character. If one of the functions of systematics is to clarify phylogenetic relationships rather than obscure them, this is surely not a valid family. In Kato's family, Tettigadidae, both males and females possess an accessory stridulating surface on the mesonotum. A similar structure is found in four genera of North American cicadas not generally considered to be closely related to the Tettigadidae. In addition Boulard (1976a) has described stridulating files on the posterior margin of the mesonotum in the genus Moana. Because of the unavailability of specimens, I have not had an opportunity to examine the stridulating mechanisms of the family Tettigadidae as recognized by Kato. However, the mere presence of accessory stridulating mechanisms now appears to be more widespread among cicadas than previously thought. Therefore, Kato's family, Tetti- gadidae, as originally circumscribed is no longer valid. The three remaining families are all diagnosed by the presence or absence and/or derivation of tymbal coverings. Only males have tymbal organs, and hence, only males can be identified by these structures. Even among males, only Boulard' s Plautillidae appear definitely to form a phylogenetic group. I think it is safe to assume that the tymbal organ itself developed prior to any accessory protective devices. This struc- ture functions to bring the two sexes into proximity for mating. Because of its importance and relative fragility, the development of strengthening or protective devices seems like the next evolutionary step. If the lack -19- of a projection of the second abdominal tergite indicates a primitive state, then other characters must be drawn upon to show any special phylogenetic relationship within the Tibicinidae. Myers (1929) was aware of this when he stated, regarding Distant1 s subfamily Tibicininae from which the family Tibicinidae is drawn, that the "Tibicininae . . . was nothing but a dumping-ground for a miscellany of unrelated forms charac- terized by a single negative quality." Some cicadas have increased the number of ribs and the degree of rib chitinization within the tymbal itself, and others have lost functional tymbals and replaced them with other sound-producing mechanisms, perhaps as a response to tymbal fragility. Even among the Cicadidae of Metcalf and Boulard, there is such a variation in second abdominal tergal projections that it is not clear whether this character developed once or many times. In our North American cicadas it ranges from the mere upturned ribbon-like acrotergite of Quesada gigas with its small lateral projections to the enormous saddlebags of Dioeropvocta avizona. If we consider only males there is at least one other obvious characteristic that may be equally important or more so from an evolu- tionary standpoint than the presence of tymbal covers. That character is the ability of some males to withdraw some genitalic structures as contrasted with those that do not possess this ability. Thus, even con- sidering only males, it is unclear whether the proposed groupings should rank at the family level. Boulard 's Plautillidae may represent a phylogenetic grouping of subfamilial status. In my opinion, the family taxon in insect systematics serves a utilitarian function. It is the lowest level to which a nonexpert in a group can easily identify a given specimen. While admittedly smaller -20- groupings may be easier to work with in some cases, I see no justifica- tion for the splitting of phylogenetically valid families unless such splitting further elucidates evolutionary and zoogeographic relationships and increases the utilitarian function of the taxon. Any division that obscures the identification of large numbers of a group at the familial level fails to meet these criteria. The proposed family groupings de- scribed by Kato, Metcalf, and Boulard are based primarily on male secondary sexual characteristics. At least fifty per cent of the world's cicadas are females. These proposals obscure the identification to family of half of the possible specimens. I, therefore, propose we maintain the family Cicadidae as a single unit until such time as more definitive and useful criteria for familial designations are discovered. Subfamilies Several attempts have been made to divide the Cicadidae into sub- families. Amyot and Serville (1843) erected two subfamilies based on the presence or absence of a reticulate condition of the veins of the fore- wing. Ashmead (1888) added a third subfamily based on the opaqueness of the wings. Wing characteristics have proven unsuitable at the subfamilial level. The reticulate condition of the veins has apparently arisen at least three times in the family, and several modern genera contain species with both completely membranous, semiopaque, or partially opaque wings (e.g., Okanagana) . More recent attempts to divide the family(ies) into subfamilies have been based on sound-producing mechanisms and their attendant coverings. Distant (1889) proposed two subfamilies: Cicadinae for those forms with the tymbals completely covered by a forward pro- jection of the second abdominal tergite and Tibicininae for those forms -21- lacking a projection of the second abdominal segment. Distant 's sub- familial divisions proved inadequate. He found many intermediate forms with the tymbals incompletely covered. For these he erected the sub- family Gaeaninae in 1905. Jacobi (1907) erected the Tettigadinae. Handlirsch (1925) attempted to erect a phylogenetic classification and established the subfamily Platypleurinae for those forms with totally covered tymbals. He united forms without tymbal covers or with the tymbals partially covered under the subfamily Cicadinae. Myers (1929) raised Tettigarata to subfamilial level. Kato's family Platypediidae was reduced to subfamilial level by Metcalf (1963). Metcalf (1963) used a combination of tymbal cover characteristics and geographic distribution to delineate subfamilies. His Tibiceninae includes Handlirsch' s Platypleurinae and geographically related forms with partially covered tymbals with the exception of the genus Neooiaada which he placed in the Cicadinae. Boulard (1976a) added Moaninae for those Cicadidae with a stridulatory surface on the posterior border of the mesonotum, Plautil- linae to encompass his family Plautillidae, and Ydieliinae as a subfamily of his Platypediidae with a stridulatory surface on the costal margin of the hind wing. Metcalf (1963) places seven of our North American genera in the Tibiceninae (Caaama, Covnuplura, Diaeropvoeta, Tibiaen, Beameria, Paaarina, and Qussada) , one in the Cicadinae (Necc-ieada) , six in the Tibicininae {Okarxzgodes , Ckanagana, TibioinGides , Clidophlaps, Magioioada, and Cicadetta) , and two in the Platypediinae (Platypedia and Neoplaty- pedia) . The last eight genera belong to the Tibicinidae of Metcalf, while in Boulard' s groupings, the last two are in the family Platypediidae. Their subfamily designations, however, remain the same. The first eight -22- belong in the family Cicadidae under both arrangements; however, here the resemblance ends. In Boulard's arrangement, by definition, Tibicen, Dicevopvocta, Covnutplva, and Caoama belong in the Platypleurinae because the tymbals are completely covered, while Quesada, Pacarina, and Beamevia would be moved to the Cicadinae because the tymbal coverings are incom- plete. The tymbal covers on Neocicada, on the other hand, are far more extensive that they are on Cicada ovni, the type for the genus Cicada from which Neocicada was removed by Kato in 1932. Individuals following Boulard's key could conceivably place specimens of Neocicada heiroglyphica in the Platypleurinae without representative samples of other Platypleur- inae genera present for comparison. A comparison of the subfamilial and familial arrangements of Metcalf and Boulard is given in Table 1. Obviously subfamily designations are dependent on family designations. The problem is that the same terms have now been used with so many varia- tions in meaning that a complete overhauling on a world-wide basis seems desirable. This is, of course, beyond the scope of this paper. Tribes Distant was responsible for much of the tribal classification of the Cicadidae in a series of papers in the "Annals and Magazine of Natural History" from 1904 to 1905. These are summarized in his synoptic catalog (Distant, 1906). His work was based on the vast collection of the British Museum. Though his output was tremendous, his techniques have been severely criticized. Myers (1929) sums up the problem thusly: If any of the [referring to Distant] divisions or tribes prove to be real morphological entities, it will be largely a happy chance, since most of them appear to be cabinet associations of superficially similar genera, for the elucidation of which a study of his collection is the first desideratum. -23- Table 1 A comparison of Metcalf's and Boulard's family and subfamily groupings of the genera of American cicadas north of Mexico. METCALF BOULARD Tibiceninae Cacama Cornuplura Diceroprocta Tibicen Beameria Pacarina Quesada CICADIDAE Platypleurinae Cacama Cornuplura Diceroprocta Tibicen Cicadinae Neocicada Cicadinae Neocicada Beameria Pacarina Quesada Tibicininae Cicadetta Clidophleps Magicicada Okanagana Okanagodes Tibicinoides TIBICINIDAE Tibicininae Cicadetta Clidophleps Magicicada Okanagana Okanagodes Tibicinoides Platypediinae Neoplatypedia Platypedia PLATYPEDIIDAE Platypediinae Neoplatypedia Platypedia -24- Metcalf s "General Catalogue of the Homoptera, Fascicle VII, Cicadoidea" (1963) gives the most recent listing of tribal affiliation. He placed the North American genera in the following tribes: Tibicenini Subtribe Tibicenaria Caoama Cornuplura Tibiaen Diaeropvoota Fidicinini Beameria Pacarina Hyantiini Quesada Cicadini Necaiaada Tibicinini Okanogodes Clidophleps Okanagana Tibiainoides Magiciaada Cicadettini Cicadetta There are no tribal designations for the two genera Playpedia and Neo- platypedia which comprise Metcalf's subfamily Platypediinae. Myers (1929) -25- felt that the tribe Tibicinnini represented a "miscellaneous collection of all those forms which will not go into any of the other gymno tympana te divisions." No improvement seems to have been made since that time. Tribal classification has not been treated in recent papers on the Cicadidae. Those characteristics which are applicable will be treated in the discussion of individual genera in this paper. The tribal taxon needs to be reworked on a cosmopolitan level. CHAPTER IV CLASSIFICATION: GENERA Linnaeus (1758) separated the genus Cicada into five subdivisions. The subdivision Manniferae became the "non saltantes" or true Cicadae. Fabricius (1775) in Systema Entomologiae introduced the genus Tsttigonia for most of what we now consider cicadas, but the two names were frequently synonymized. The genus Cicada remained the only generic designation of the group for a long time. Latrielle founded the genus Tibicen in 1825. The name was simply listed without description but with the naming of C. plebeja Scop, as type. Some authors tried to use the name with various interpretations, but most ignored it. Several species had been named as types of the genus Cicada, among them the species Cicada tibicen. In 1914, Van Duzee firmly stated he felt Lamarck (1801) intended to name Cicada ovni as the type of the genus Cicada, thus freeing the name "tibicen" to be used for another genus. He accepted ptebeja as the type of the genus Tibicen following the "International Code" and two years later established many of our North American species as members of this genus in his Check. List of the Hemiptera of America, North of Mexico. Among our American genera north of Mexico, the next genus to be named was Cicadetta, Kolenati (1857). Diceroprccta appeared in a key in Stal's Hemiptera insularum Philippinarum in 1870 but was not widely used until Davis (1923) moved several North American species from the genus Tibicen to Dlcevopvccta. Uhler named Flatypedia in 1888. Cacama was named by Distant in 1904, and the same author named Pacar-ina, Qiiesada, -26- -27- and Okanagana in 1905. Distant added Tibicinoides in 1914 and Van Duzee named Clidovhleps in 1915. All but one of the remaining genera were named by William T. Davis. Those named by Davis include Okanagod.es, 1919a; Neoplatypedia, 1920; Magicicada, 1925; Beaw.evia, 1934; and Covnuplura, 1944. In 1932, Kato transferred our remaining North American representa- tives of the genus Ciaada to their own genus, Neociaada. The first attempt to list specifically the genera of America north of Mexico was Van Duzee 's checklist of 1916 followed the next year by his catalogue of the same genera and species. Although Van Duzee listed six- teen genera, the same number we have now, only eight of the names remain the same. Melampsalta has been synonomized with Cicadetta. Our repre- sentatives of Proarna have become Beameria; Tibicina have become Magicicada; and Cicada have become Neociaada. Fidieina, Odcpoea, Tettigades, and Herrera were apparently erroneously attributed to this geographical re- gion by early writers. The only other paper to deal with the genera as a whole is Davis' 1930 distributional study. He also lists sixteen genera with only twelve that correspond to our current list. Davis omits Fidieina, Odopoea, and Revvara and adds Neoplatyvedia, Diceroprocta, and Okanagodes. He replaces Tibicina. with Magicicada. Although Davis retains Tettigades as a United States genus, based on Cochise County records, I have never seen specimens of the genus collected north of Mexico. I have collected extensively in Cochise County, Arizona, where Davis reports they occur. I have also consulted with Dr. Thomas Moore of the University of Michigan, who has collected in both the United States and Mexico, and he assures me that the northern distributional limits of Tettigades lie far south of the United States border (Moore, 1977, personal communication). Beameria, -28- Neooioada, and Cornuplura were not yet named when Davis wrote his 1930 paper, and the synonomy of Melampsalta with Cioadetta was not widely accepted. The most recent listing of cicadas is the world wide catalogue of Metcalf (1963). Metcalf occasionally indicates what he thinks is an erroneous location, but he usually reiterates locations given by authors without comment. His generic nomenclature is up to date. Early writers were often obscure in listing their localities, thus one can extract twenty-four possible genera for North American cicadas north of Mexico from Metcalf's list. Errors in Metcalf's catalogue contribute additional genera, for example, Neooiaada chisos is still listed under the genus Cicada. The current list of American genera from the region north of Mexico is as follows: 1. Beameria, 2. Caoama, 3. Cioadetta, 4. Clidophleps, 5. Comwplupa, 6. Dicevopvoota, 7. Magicioada, 8. Neooiaada, 9. Neoplatypedia, 10. Okanagana, 11. Okanagodes, 12. Paoarina, 13. Platypedia, 14. Quesada, 15. Tibiaen, 16. Tibicinoides . CHAPTER V GENERAL MORPHOLOGY The largest Homoptera are found in the family Cicadidae. These insects are generally characterized by a rather short, stout body with moderately long wings. The head is short, but wide, with prominent eyes and three conspicuous ocelli. In the genera north of Mexico, the meso- thorax is the largest thoracic segment. Males of most genera contain a sound producing tymbal organ lateral to the first abdominal segment. A chordotonal organ is indicated by a lateral bulge on the second abdominal segment in both sexes. Although several writers have written on specific aspects of both the internal and external anatomy of cicadas, Myers' study (1928) remains the most comprehensive treatment of cicada morphology. A number of specialized terms have been used in the past to refer to features of cicada anatomy. This paper incorporates several of these terms into the descriptions and keys in order to provide continuity with past work. The following discussion is presented to clarify terms used in the keys and generic descriptions. General characteristics of cicada morphology are illustrated by diagrammatic views of the dorsal and ventral surfaces (Figure 1) . -29- Figure 1. A, dorsal view of a cicada. The following structures are labeled: clypeus (clp) , epicranium (ep) , pronotum (pr) , pronotal collar (pc) , prescutum (psc), scutum (sc) , scutellum or "cruciform elevation" (scl) , metathorax (mt), tymbal cover (tc), pygofer (p). The left tymbal cover is cut away to reveal the tymbal organ (tym). In this example the mesothorax covers most of the metathorax. The arrow points to the loca- tion of the lateral carina when viewed laterally. B, ventral view. Legs have been cut away below the coxae (ex) . The following structures are labeled: clypeus, operculum (op), propleuron (prp), meron (me), hypandrium (h) , epimeron of the metathorax (mep) . The right operculum is cut away to reveal the folded membrane (fm) and the mirror or tympanum (m) . Roman numerals in both figures indicate abdominal segments . -31- B -32- General Body Proportions Two measurements are given for each genus to provide an indication of general range of size of members of the genus. Length of body is measured from the apex of the clypeus to the tip of the abdomen. Expanse of wings is the greatest expanse of the forewings. This measurement is the only wing measurement consistently given in species descriptions. The relationship of abdomen length to overall length of the body is also indicated. This relationship usually is characteristic of a genus. The variability in size range is greater, of course, in specimens of the larger genera. While size ranges overlap considerably, from a practical standpoint, size can often narrow the number of genera under considera- tion when identifying an individual specimen. Thus, a very large cicada would not fall in the range of Tibic-inoid.es, Beameria, or Pacarina, and a very small cicada is unlikely to be a Quesada, Tibicen, or Covnuplura. Head The cicada head contains several characteristic features. Tradi- tional measurements and nomenclature of the head are in some cases obscure and in others a point of controversy in the literature. A characteristic measurement used by Distant and others is a comparison of the width of the head, including the eyes, versus the width of the "base" of the mesonotum. Torre-Bueno (1962) defines the base of a thoracic structure as "that part nearest the abdomen" ; however, this is a meaningless measurement in cicadas. Previous writers obviously meant the visible anterior edge of the mesonotum. Since the real anterior edge of the mesonotum is overlapped by the collar of the pronotum, a -33- sometimes curved structure, this measurement is also awkward. Therefore, the width of the head, including the eyes, in the following descriptions is compared with the width of the mesonotum measured at its broadest point between the forewings, excluding the axillary sclerites. The eyes in cicadas are prominent and may be narrower, in a line with, or extend laterally beyond the anterior angles of the pronotum. This relationship is usually obvious. However, a straight edge may be lined up with the lateral edge of the eye to determine its relative posi- tion with the anterior lateral angles of the pronotum. The definitions of the head regions are controversial, also. Snodgrass (1935) defined the clypeus as the "region of the cranial wall on which the dorsal dilator muscles of the . . . cibarium take their origin." The frons was interpreted as a triangular region which "bears the median ocellus on its upper part." When a frontoclypeal or epistomal suture is present, it separates these two regions. The anterior tentorial pits are normally associated with the lateral ends of this sulcus and mark the point of articulation with the anterior arms of the tentorium. In some insects the pits have migrated medially on the sulcus. When a frontoclypeal suture is lacking, a line drawn between the anterior tentorial pits is used to delineate the frontal and clypeal regions of the head . In the cicada the median facial plate is bordered both dorsally and laterally by a continuous suture. The anterior tentorial pits are located in the upper half of the lateral portion of this sulcus. DuPorte (1962) interpreted the transverse portion of the sulcus as a "transf rontal ridge such as found in mantids." The lateral regions between the trans- verse portion and the anterior tentorial pits, he called "frontogenal -34- ridges," and those distal to the pits, he interpreted as "clypeogenal ridges." He supported this view by stating that the anterior mandibular articulation would then correspond to that typically found in Hymenoptera. He further stated that the entire head evolved from a hypothetical psocid-like ancestor. In his interpretation, the frons would consist of the region anterior and dorsal to a hypothetical line drawn between the tentorial pits, and the post clypeus would be the region posterior to this line. In reality this interpretation is a return in part to the de- scriptions of earlier morphologists and taxonomists who called the entire median facial plate the "front" or frons and the remainder of the epi- cranium the "disk, of the vertex." This terminology was used prior to Snodgrass' detailed morphological studies. DuPorte's interpretation is interesting but requires several assump- tions: 1. The frontoclypeal sulcus has disappeared or never existed; 2. the muscles of the cibarium have invaded the frons; 3. The modern cicada head has developed or evolved from both specialized orthopteran and hymenopteran characteristics; 4. The entire head, and by extension, the rest of the organism developed from a psocid-like ancestor. Both Snodgrass and Kramer (1950) cited evidence of a "Y" shaped frontal suture encompassing the median ocellus. They interpreted the arms of this suture as the demarcation of the sides of the modern frons. Kramer further used these ridges as part of his phylogentic evidence that ancestral cicadas branched from a common ancestoral stem with cercopids, cicadellids, and membracids much earlier than the separation of the three from each other. In an attempt to verify DuPorte, I felt that if even part cf the iateral edges of the median facial sclerite split during ecdysis, it would be evidence in favor of his theory. A careful examination of exuviae in my collection indicated that the ecdysial split terminates at the trans- verse sulcus. This is not, however, inconsistent with other writings of DuPorte (1977). The dorsum of the cicada head contains three distinct regions, a horizontal vertex, a sloping, sometimes vertical, middle region anterior to the vertex containing the median ocellus, and an anterior horizontal region containing the dorsum of the median facial plate flanked by the supraantennal plates. If we accept DuPorte 's ideas, what should we call the central section? If we accept Snodgrass' interpretation, the length of this segment is equivalent to the length of the frons. There is a much simpler explanation for the dorsal structures of the cicada head than DuPorte 's theory. The clypeus has obviously expanded to accomodate the dilator muscles of the cibarium. If it expanded upward as well as outward, the frontoclypeal sulcus would lengthen around the sclerite. Without moving the tentorial pits, the sulcus would attain the current broad "U" shape. The frons would be subsequently shortened as the clypeus expanded. This interpretation does not require the loss of one sulcus and the acquisition of another, the invasion of the frons by the muscles of the cibarium, or other specialized characteristics except those associated with the more efficient acquisition of food. I have no evidence either in support of or against DuPorte' s theory. DuPorte worked with an unidentified Tibiaen. Until I see additional studies of closely related Homoptera, including Tettigarata, which apparently retains a vestigial subgenal suture (Kramer, 1950), I prefer the simpler explanation. Therefore, in the following descriptions, the length of the frcns will refer to the more or less vertical portion of •36- the head, as distinct from the vertex, and will be compared with the dorsum of the clypeus. The epicranium will be assumed to end with the epistomal or frontoclypeal suture (see Figure 2) . Cicadas have three ocelli. The two lateral ocelli lie on the ver- tex of the head, the middle ocellus is located on the frons. The rela- tionship of the distance between the two lateral ocelli versus the distance between a lateral ocellus and the corresponding eye usually is characteristic of a genus. Measurements were made from the interior margin of the eye to the exterior edge of the ocellus and between the medial edges of the two lateral ocelli. The supraantennal plates lie above the insertion of the antennae. The anterior edge of these plates may form a more or less continuous line with the apex of the clypeus or the clypeus may protrude substantially beyond the margins of the supraantennal plates. The dorsal shape of the clypeus and the extent of its protrusion are generically characteristic. The clypeus is flanked laterally on the "face" by the lora (singular, lorum) sometimes referred to as the "cheeks." The rostrum or proboscis is an extended mouth piece representing the sucking beak in cicadas. The rostrum is comprised of an elongated labium forming the outer sheath and containing the mandibular and max- illary bristles. The maxillary bristles interlock centrally forming two primary ducts, one for the egestion of salivary fluid and one for the ingestion of food. The length of the rostrum may be species specific within a genus; however, a prescribed range of lengths is usually characteristic of a genus. Thus, Okanagana have relatively short rostra, extending within the range of the middle coxae; whereas, Caaama have long rostra extending to or beyond the hind coxae. Figure 2. The cicada head. A, face or ventral side showing position of eyes (e) , ocelli (oc) , frons (f r) , supraantennal plates (sap) , lora (1) , postclypeus (pclp) , anteclypeus (aclp) , labrum (lm) , rostrum (ros) . B, dorsum showing the eyes, ocelli, frons, supraantennal plates, the dorsum of the clypeus (clp) , and the frontoclypeal or epistomai suture (fcs). The lateral circles just mediad to the eyes mark the location of an unidentified sensory organ. C, cross section of the rostrum showing the relative positions of the man- dibular (md) and maxillary (mx) setae. The large central lumen is the food channel. The smaller lumen to the right is the salivary channel. Four smaller luma, one in each of the setae form passageways for nerves and tracheae. The labium (lab) forms the outer sheath. -38- -39- Thorax The pronotum is characterized by two pairs of diagonal grooves. The posterior margin is broad and ends with the dilated lateral posterior angles. The posterior margin is frequently referred to as the pronotal collar. The lateral margins may be ampliated or dilated. Laterally the pronotum joins the propleuron. If the pronotum is ampliated, when viewed laterally, this juncture forms a continuous keel or carina extending the length of the pronotum. The extent of the lateral amplification deter- mines the extent of the carina. The lateral edges of the pronotum are usually smooth in the genera found north of Mexico. They are irregularly toothed or jagged in Quesada and in some species of Okanagana. Occasion- ally the lateral edges will bear one or two spines. The mesothorax is the largest thoracic segment in the North American genera of cicadas. The anterior part of the notum projects beneath the pronotum forming an anterior phragma. A "U" shaped prescutum is located in the center of the anterior portion of the notum. The scutum occupies the greater part of the notum. The scutellum forms a raised ''X" which has been termed the "cruciform elevation" by taxonomists. In some genera the mesonotum is ridged where the forewing sits at rest. A portion of this ridge may project medially on the anterior part of the notum near what is sometimes called the "shoulder." When this occurs, the projec- tion is finely striated and used as an accessory sound producing mechanism with the wing acting as the plectrum. Sometimes the ridged portion bears fine, even striations (see Figure 3). The metathorax is very short dorsally. In half of the genera found north of Mexico, the scutellum of the mesothorax overlies and conceals Figure 3. A portion of the thorax of an okanaganoid cicada showing striations on the mesonotum. Large arrow points to the stridulitrum. Small arrow points to the presumed plectrum on the forewing. Terminology follows Ashlock and Lattin (1963) . The stridulitrum is frequently located in a pale area on a dark background. This area is indicated on the figure. Drawn from Clidophleps blaisdelli. -41- -42- the central portion of the metathoracic tergum. Ventrally, the epimera in males are usually produced caudally forming the opercula, or lower covers of the tymbal organs. Legs The legs of cicadas are normally segmented. They are not modified for jumping as in some of their closest relatives. There are three tarsal segments, but no pul villi between the tarsal claws. The foreleg of the nymph is fossorial. In the adult the fore femora retain a lessened fossorial expansion and usually bear spines on the ventral margin (Figure 4). The tibia are subcylindrical. The metathoracic mera are elongated and form projecting triangular structures. These projec- tions are the meracanthi of some older works, but more recent publications use mera (singular, meron) , e.g., Kramer (1950), Bullough (1950). Wings Wing notation is by no means fixed for the family. The most common deviation is the proximal portion of the radius. Some authors combine this portion of the radius with the base of the media where it emerges from the basal cell or the arculus. This of course modifies the notation of the veins at the apex of the wing and also the notation of the inter- vening cells. The following descriptions follow the modified Comstock- Needham interpretation of venation accepted by Myers (1928, 1929), Cooper (1941), Kramer (1950), and others. This is the interpretation most commonly given in modern general textbooks (e.g., Borrer and DeLong, 1971). In this interpretation the radius is united with the subcosta Figure 4. Femur of a cicada foreleg showing expanded configuration and spines on the ventral surface. Drawn from Okanagana fitrm'.pennis . -44- -45- proximal to the body. This interpretation is used for most original descriptions of North American genera and species. The following remarks, therefore, are consistent with prior descriptions. The modified Corns tock-Needham system, which I am following, is shown in Figure 5. Cell notation in the Comstock-Needham system is complex. The cells or areoles in cicada wings are often referred to by groups, for example, the eight apical areas or marginal cells or the ulnar areas. This is the system of cell notation used and diagrammed by Simons (1954). Simons' notation is simpler and lends itself to use in keys and the more generalized descriptions at a generic level. Simons' system of cell notation is shown in Figure 5 and is utilized in the following text. A special feature of the forewings is the presence of the nodal line. This line runs from the nodus or node of the costal margin across the width of the wing. Its presence is marked by minute breaks in the sclerotization of some of the principal vein branches. The function of this line became apparent to me during a sequence of a movie showing Magiaicada sevtendeo-im in the stages of the final molt to an imago (Moore and Kausch, 1975). The wings are apparently folded along this line in the last instar nymph prior to emergence as an adult. The line is well marked in some members of the genus Tibiainoides by a rudimentary vein. The line apparently is also present in the Cicadelloid family Hylicidae (Kramer, 1950). The hindwings of some genera are susceptible to individual variation. Therefore, hindwing characteristics have not been utilized in this dissertation. Figure 5. Cicada forewing showing two systems of notation in current usage. A, cell notation used by Simons (1954) . Abbrevia- tions are as follows: A, anal cell; arc, arculus; Ba, basal cell; C, costa; Cu, cubital cell; Ml, M2 , etc., marginal cells; Me, medial cell; N, nodus; Ul, U2, etc., ulnar cells; 1st and 2nd equal the first and second crossveins. B, Comstock-Needham system used in current textbooks of entomology, Abbreviations used in the notation are longitudinal veins — C, costa; Sc, subcosta; R, radius; M, media; Cu, cubitus; A, anal. Crossveins — m, medial; m-cu, medio-cubital ; r-m, radio- medial. Cells are named according to the longitudinal vein on the anterior side of the cell. The general position of the nodal line is indicated by dots in both A and B. -47- -48- Abdomen The first two abdominal segments are modified for the production and reception of sound. Pringle (1954, 1957) gives detailed accounts of the morphology of this region. The exterior cuticle is depressed and thickened forming a wide vertical groove. This groove "is divided into dorso-lateral and ventro-lateral portions by a horizontal ridge projecting forwards from the lateral angle of the abdomen" (Pringle, 1957). Ven- trally the groove is bounded by two membranes, an anterior "folded membrane" that permits the abdomen to move relative to the thorax and a posterior chordotonal "tympanum" sometimes termed the "mirror." At the base of the groove is a heavily sclerotized skeletal structure that forms the basal attachment of the tymbal muscles and projects dorso-laterally to form the "chitinous V." Dorsally the groove is bounded posteriorly by a strongly sclerotized surface, while the anterior surface is the sound producing "tymbal organ" or simply "tymbal" (Figure 6) . The tymbal organ itself is a ribbed membrane whose buckling produces the sound vibrations associated with cicadas. An "auditory capsule" is indicated exteriorly by a lateral bulge on the second segment. Interiorly this capsule contains a number of chordotonal sensilla connected to the thoracic ganglion by an auditory nerve running forward through the base of the chitinous "V" to the thoracic ganglion. In Neoaiaada and Cicada this capsule has migrated ventrally. Pringle (1954, 1957) and Vasvary (1966) detail the musculature and nervous connections of this area in Platy pleura capztata and Tibicen ohlovomeva, respectively. Abdominal segments III through VI are not specialized. The terga form lateral angles and project across the lateral areas of the ventral Figure 6. Structures associated with the first and second abdominal segments in male cicadas. A, vertical groove, viewed laterally with left opercula and tymbal cover removed. Structures shown are tymbal organ (tym), auditory capsule (a), horizontal ridge (hr) , folded membrane (fn), chitinous "V" (V), tympanum or mirror (m) , opercula (op), posterior coxae (ex), meron (me). The direction of the thorax (tho) and abdomen (abd) are indicated. B, posterior view of the same area. The tymbal cover (tc) and tymbal organ (tym) are re- moved on the right to reveal the sclerotized posterior surface. Tymbal muscles (t mus) are shown. Drawn from Tibicen duryi. -50- -51- side of the abdomen. The terminal segments of the abdomen are discussed under the heading "sexual characteristics." Sexual Characteristics One of the primary functions of this study is to enable the reader to identify easily specimens "in hand" to genus. For that reason only ex- ternal portions of the segments bearing genitalia have been described. These are the parts that are readily seen or easily extracted without complicated dissection. Numerous other genitalic structures are available for use at the specific level. The terminal segments of the abdomen are modified by the genitalic appendages. The ninth and tenth segments form the external genitalia. The eleventh segment is small and bears the anal style. The ninth tergite in both sexes forms the pygofer. The pygofer in cicadas is a simplified structure forming nearly a complete sclerotized ring. Ventrally the ends of the tergite may meet, but they remain un- connected in females to allow for the extrusion of the ovipositor. The posterior portion of the ventral region in males is invaginated into the segment to form the genital chamber that holds the phallus. "Genital plates and genital valve as well as styles and connective are absent" (Tuxen, 1970) . The tenth segment in males bears an interesting structure apparently functioning to protect, and in some cases, hold the phallus. This structure may be united or simple as in Tibi-oen and the okanaganoid genera, or it may be bifurcated, consisting of a pair of structures as in Cioadetta, Magicioada, and Diceropi'oota. It has been called by a variety of names, e.g., "copulatory claspers" (Myers, 1928, 1929), "lateral lobes" (Snodgrass, 1935), "anal hooks" (Tuxen, 1970), "ventral processes" (DuPorte, 1977). Taxonomists call it the "uncus," and it -52- will so be named in this study. The uncus has formed the basis for both generic and specific separation especially in the cicadas found in North America north of Mexico. Six western genera are characterized by an elongated uncus lying dorsally over the phallus. The hypandrium or eighth sternite, a "boat-shaped" sclerite, is correspondingly elongated and protects the phallus from below. The uncus in these genera does not retract into the abdomen. In the remaining genera the pygofer may be substantially withdrawn into the eighth segment. The uncus maintains a ventral position in the noncopulating male. It is hidden ventrally by the correspondingly shorter hypandrium (see Figure 7). In females the seventh sternite forms the subgenital plate. Its basic shape is frequently characteristic of a genus. The eighth sternite is not visible. It is greatly reduced in size and consists of two lateral sclerites lying under the seventh sternite. In some Tibiaen and Covnwpluva the eighth sternite may project into hooks medially. The female possesses three pairs of appendages, or "valves" that make up the ovipositor and its sheaths. The central pair is fused distally. It is united with the middle pair by a series of interlocking grooves that prevent lateral movement but allow the lateral pieces to slide longi- tudinally relative to the central piece. The middle pair of valves are highly chitinized and possess cutting teeth or edges. The outer pair of valves form the sheath of the ovipositor (Figure 7). Internal Structure Revealed by Radiographs Systematists have recognized for a long time that characteristics other than external anatomical features could be useful in identification and in correlating relationships of various taxcnomic units. Numerous Figure 7. External genital bearing segments of cicadas. A through E are males. A, lateral view of retractable form with the pygofer (p) and uncus (u) pulled out; B, same as above in a normal resting position; C, caudal view. D, lateral view of nonretractable form with the uncus raised; E, same in a normal resting position with the uncus lying in the trough of the hypandrium (h) . F through H show female characters. F, caudal view showing hooks of sternite VIII lying under the subgenital plate (sp) . This character occurs in Cornuplui'a and some Tibioen. G, ventral view showing the pygofer (p) surrounding the ovipositor. H, female ovipositor showing saw valves (vl) , middle piece (v2) , sheaths (v3) . Terminology after Myers (1929) . -54- H -55- approaches have been taken ranging from simple internal dissections to complicated chemical extractions. While most of these techniques yield valuable information, they may be impractical for the average entomologist to use. They frequently require fresh specimens or at least freshly preserved specimens for best results. Many techniques are extremely ex- pensive. They all require destruction of part or all of the specimen, and, therefore, cannot be used on museum types. Professor H.L. Cromroy of the University of Florida suggested I explore the use of low energy x-rays (soft x-rays) to elucidate internal characteristics. The results are only preliminary, but a few remarks can be made regarding the technique. The model [Faxitron 804] used is small and fits on a table-top. It is a relatively inexpensive piece of scientific equipment and is as easy to operate as a kitchen oven. It in no way alters or damages the appearance of the specimen and, therefore, should be safe to use even on type specimens. Two series of radiographs were taken. Dorsal views were made at 50 KVP (kilovolt potential) with exposures ranging from 45 to 60 seconds, and ventral views at 25 KVP with an exposure time of 60 seconds. Polaroid P/N 55 film was used, and the resulting radiographs were en- larged for analysis. At these exposures and times, elements of dried internal musculature are the most obvious features revealed. The median dorsal indirect flight muscles show clearly in both sexes. The other thoracic musculature is less distinct. Elements of the reproductive musculature are also seen in some of the pictures. The most significant muscular feature of taxonomic value revealed is the generalized shape of the male tymbal muscles. Pringle (1954) defines the tymbal muscles as, "The main muscles of the sound-producing apparatus, attached basally to the base of the -56- chitinous V and distally to a thin approximately circular disk from the centre of which a flat apodeme runs to the tymbal." While the muscle runs dorso-ventrally through the insect, a characteristic pattern is shown by x-rays made of a dorsal or ventral view. Thus the four North American genera having complete tymbal covers and belonging to the tribe Tibicenini have a characteristic deep V shape to the x-rayed tymbal muscle. The V is united posteriorly forming a Y in both Tibioen and Cornuplura. This pattern holds for both the parallel sided and gently tapering forms of Tibicen discussed later in the text. Kato (1961) has also taken radiographs of cicadas. He pictures two genera of Tibicenini found in Japan (Kato, 1961, Plate XIX). The x-rayed tymbal muscle in Tibicen bihamatus (Motschulsky) illustrated by Kato agrees perfectly with the pattern seen in North American Tibioen, while Cryptotympana japonensis Kato lacks the united posterior extension of the V. Caoama also lacks the posterior extension, its V shape being broader and shallower than Tibicen. The pattern in Dicevopvocta shows the greatest deviation from the other Tibicenini. Although the central posterior V is present, the lateral connections are broader. Additional partial anterior muscles extend upward, almost forming a hexagonal pattern. The pattern in Bicevopvocta is very similar to that found in Magicicada which lacks tymbal covers completely. Vacavina has a similar pattern, but the arms do not meet posteriorly. In Neooiaada the distal connections ara narrow. The four okanagancid genera, Okanagana, Tibicivjaides , Okanagodes, and Clidophleps exhibit a rather flat latitudinal pattern indicating a more vertical structure within the insects. This pattern appears broadest in Okanagana. Quesada shows a broad latitudinal pattern and Beamevia falls between Okanagana and Quesada. Cicadetta has a narrow pattern projecting -57- slightly anteriorly. X-rays of Platypedia and Neoplatypedia reveal no sign of tymbal muscles. While all the patterns of tymbal muscles generated by North American genera occurring north of Mexico appear to be deviations of two basic patterns, they do not group the genera com- pletely around traditional lines. The most notable exception is the pattern exhibited by Magioicada, resembling more closely the muscular pattern in the group containing tymbal covers rather than the group lacking tymbal covers. The tymbal covers in Beamer*ia and Quesada are minimal. Handlirsh (1925) felt that cicadas with partial tymbal covers should be considered more closely related evolutionarily to those lacking covers than to those with complete covers. The two genera with extensive, but not complete covers, Pacarina and Neocicada, are more similar to those genera with tymbal covers than they are to those without. Although variation in the tymbal musculature patterns found in the North American genera are not as striking as one might hope for, quite different pat- terns are illustrated by Kato for the genera Tanna and Graptovsaltvia from Japan, indicating that both this character and the technique that reveals it are worth pursuing further. Figure 8 shows examples of the radiographs . Other morphological features exhibited by all or several of the x-ray radiographs are the shape and position of the frontoclypeal suture, the insertion of the forelegs, and the extent of ovarian development. All the specimens x-rayed were dry, pinned specimens. Therefore, care must be used in interpretation of the radiographs. Comparative studies need to be made between fresh specimens and dry ones to see the extent anc- variation of change with time. Various exposures and times may reveal different structures. For these reasons, the above analysis Figure 8. Radiographs of cicadas. A though H are males. Arrows point to the location of the tymbal muscles. A, Tibioen, and B, Coimuplui'a , show a Y configuration. C, Cacama, shows a broad V. D, Dicevoprocta, and E, Magioicada, are almost hexagonal. F, Quesada, and G, Tibicinoides , are transverse. H, Platypodia, lacks a tymbal muscle. I through L are females. Large arrows point to the ovaries. Small arrows on I, Quesada, point to the f rontoclypeal sulcus and the insertion of the foreleg. The small arrow on J, Tibiaen, points to the muscles surrounding the ovipositor. K and L are Magioiaada and Cacama, respectively. E, G, and H are enlarged. The remainder approximate the actual size. -59- r wv « / ^ * -60- is regarded as both speculative and preliminary. The technique does show promise, however, not only in taxonomy but in ecology as well. Struc- ture and utilization of nests, nymphal development, analysis of parasitism, and infestations within plants are but a few of the possibilities. The greatest advantage of low energy x-ray radiography in taxonomy is that it reveals additional information without damaging the source. CHAPTER VI KEYS TO THE GENERA Males 1 Posterior margin of metanotum partially covered by mesonotum; lateral anterior projections of 2nd abdominal tergite covering or partially covering the tymbal organ (Fig. 1) 2 1' Posterior margin of metanotum completely visible behind mesonotum; lateral anterior projections of 2nd abdominal tergite absent (Fig. 12) 10 2 (1) Tymbal covers complete dorsally; opercula meeting or nearly meeting (Fig. 2) 6 2' Tymbal covers incomplete dorsally; opercula may meet (Fig. 20) ... 3 3 (2') Tymbal covers triangular and concave medially; opercula meeting or nearly meeting (Fig. 20) Pacarina 3' Tymbal covers not triangular or concave medially; opercula separated (Fig. 9) '. '. . . . 4 4 (3') 1st and 2nd crossveins of forewings parallel (Fig. 5) 5 4' 1st and 2nd crossveins of forewings not parallel (Fig. 9). . .Becoverio. 5 (4) Lateral edges of pronotum smooth (Fig. 16) Neoc-ijada 5' Lateral edges of pronotum jagged or irregularly toothed (Fig. 22) Quesada 6 (2) Ninth abdominal tergite produced posteriorly to a central spine or point (Fig. 6) 7 6' Ninth abdominal tergite without a central spine (Fig. 14) 9 Diaeropr>oaia and Tibijen in part 7 (6) Width of head including eyes ir.uch narrower than the width of the mesonotum; length of body less than 2 1/2 times the width of the mesonotum; abdomen broadly rounded caudally (Fig. 10) . . .Caocvna -61- -62- 7' Width of head including eyes about as wide or wider than mesonotum; length of body at least 2 1/2 times the width of the mesonotum; abdomen tapering caudally (Fig. 1) 8 8 (7') Ninth abdominal tergite with a pair of spines protruding backward from the ventral edge (Fig. 13) Cormuplura 8' Ninth abdominal tergite lacking ventral spines (Fig. 23 and Fig. 7) Tibioen 9 (6') Length of body greater than 35 mm; uncus simple (Fig. 23) Tibiaen 9' Length of body less than 35 mm; uncus bifurcated (Fig. 14) Dioeroproota 10 (1') Uncus retractable (Fig. 7) 11 10' Uncus exposed; hypandrium elongated (Fig. 7) 12 11 (10') Medial and cubital veins joined when emerging from basal cell of forewing (Fig. 11) Cicadetta 11' Medial and cubital veins emerging separately from basal cell of forewing (Fig. 15) Magiciaada 12 (10') Tymbal organs present (Fig. 1) 14 12' Tymbal organs absent (Fig. 21) 13 13 (12') Eight marginal cells in forewing (Fig. 21) Platypedia 13' Seven marginal cells in forewing (Fig. 17) Neoplatypedia 14 (12) Pronotum flared laterally forming longitudinal ridge or carina when viewed from the side; ocelli variously colored 15 14' Pronotum constricted, rounding laterally; ocelli ruby red (Fig. 19) Okanagodes 15 (14) Marginal cells of forewing about 1/2 the length of ulnar cells Ul and U2 (Fig. 24) Tibieenoides 15' Marginal cells of forewing at least 2/3 the length of ulnar cells Ul and U2 (Fig. 5) 16 16 (15') Costal margin of radial cell at least 2 1/2 times longer than the medial vein anterior to the first branch (Fig. 18) Okanagana 16' Costal margin of radial cell less than 2 1/2 times longer than the unbranched segment of the medial vein (Fig. 12) .... Clidophleps -63- Females 1 Posterior margin of metanotum partially covered by mesonotum (Fig. 1) 2 1' Posterior margin of metanotum completely visible behind mesonotum (Fig. 12) 11 2 (1) Width of head including eyes about as wide or wider than width of mesonotum (Fig. 1) 3 2' Width of head including eyes much narrower than the width of the mesonotum (Fig. 10) Cacama 3 (2') First and second crossveins of forewing parallel or nearly parallel (Fig. 5) 4 3' First and second crossveins of forewing not parallel (Fig. 9). . . .9 4 (3) Longitudinal veins with infuscated dots near the ambient vein (Fig. 16) Meoaicada 4' Longitudinal veins without infuscated dots near the ambient vein (Fig. 5) 5 5 (4') Lateral edges of pronotum jagged or irregularly toothed (Fig. 22) Quesada 5' Lateral edges of pronotum smooth (Fig. 1) 6 6 (5') Subgenital plate sinuous and/or length of R4+5 between the first and 2nd crossveins equal to or greater than length of R4+5 from first crossvein to the ambient vein in the forewing (Fig. 14) Diceroprocta 6' Subgenital plate produced into two symmetrical, smooth lobes; length of R4+5 between the first and second crossveins less than the length of R4+5 from the first crossvein to the ambient vein in the forewing (Fig. 23) 7 7 (61) Eighth abdominal sternite visible as 2 hook-like projections beneath the subgenital plate when viewed caudally (Fig. 7) . . 8 Cornuplura and Tibioen in part 7' Eighth abdominal sternite not visible beneath subgenital plate or or lacking hook-like projections (Fig. 23) Tibicen 8 (7) Basal cell of forewing green or brown (Fig. 23) Tibicen 8' Basal cell of forewing predominantly black (Fig. 13) ... . Cornuplura 9 (3') Length of 7th marginal areole more than 2 times the width (Fig. 14) Diceroprocta -64- 9' Length of 7th marginal areole not greater than 2 times the width (Fig. 9) 10 10 (9') Eyes extending laterally away from pronotum; abrupt color change on face (Fig. 20) Paearina 10' Eyes not extending laterally away from anterior edge of pronotum; no abrupt color change on face (Fig. 9) Beameria 11 (1') Medial and cubital veins joined when emerging from basal cell of forewing (Fig. 11) Cioadetta 11' Medial and cubital veins emerging separately from basal cell of forewing (Fig. 5) 12 12 (11') Nodus of forewing located centrally on the costal margin (Fig. 5) 14 12' Nodus of forewing located on the distal third of the costal margin (Fig. 21) 13 13 (12') Eight marginal cells in forewing (Fig. 21) Platypedia 13' Seven marginal cells in forewing (Fig. 17) Neovlatuvedia 14 (12') Pronotum expanded laterally forming a longitudinal carina for its entire length 15 14' Pronotum rounded laterally, lacking a complete longitudinal carina 17 15 (14) Marginal cells of forewing about 1/2 the length of ulnar cells Ul and U2 (Fig. 24) Tibioenoides 15' Marginal cells of forewing at least 2/3 the length of ulnar cells Ul and U2 (Fig. 5) 16 16 (15') Costal margin of radial cell at least 2 1/2 times longer than the medial vein anterior to the first branch (Fig. 18) Okanagana 16' Costal margin of radial cell less than 2 1/2 times longer than the unbranched segment of the medial vein (Fig. 12). . . . Clidophleps 17 (14') First crossvein of forewing oblique (Fig. 15) . . . . Magiciaada 17 First crossvein of forewing perpendicular (Fig. 19; . . . .Gkanagodes CHAPTER VII Beamevia Taxonomy Beamevia Davis (1934, p. 47) Type Species Beamevia venosa (Uhler) (Davis, 1934) = Pvnanasis venosa Uhler = Pvoavna venosa (Uhler) Species There are two species in this genus, Beamevia venosa (Uhler) and 3. wheelevi Davis. Both occur in North America north of Mexico. Descriptive History Davis' remarks are less a description than a comparison of the new genus with the two genera in which Beamevia venosa was previously placed. Neither Pvuanasis nor Pvoavna occur in North America north of Mexico so these comparisons are of little value in distinguishing this genus from other American genera north of Mexico. -65- -66- Description General Body Proportions Length of body 11.0 to 17.0 mm Expanse of forewings 31.0 to 40.0 mm The abdomen represents approximately one-half the body length. Head Width of head including eyes about the same as the width of the meso- notum; eyes not prominently projecting laterally; epicranium in a con- tinuous gentle slope with dorsum of clypeus; width between ocelli about the same as width between lateral ocelli and eyes; clypeus rounded and prominently produced beyond the supraantennal plates; dorsum of clypeus longer than f rons ; rostrum reaching posterior coxae. Dorsum and venter of head similarly colored. Thorax Pronotum adpressed laterally except at posterior angles, lacking a continuous lateral carina. Length of pronotum shorter than length of mesonotum; mesonotum obscuring central portion of metanotum. Opercula in males large, broadly rounded, separated medially by a third, centrally projecting schlerite. Legs Anterior femora with two prominent spines beneath, sometimes with a minute third spine distally. Posterior mera triangular, frequently curved . -67- Wings Forewing venation is illustrated in Figure 9. Both wings hyaline. First crossvein in forewing perpendicular, second crossvein slightly oblique, first and second crossveins not parallel; medial and cubital veins arising separately from the arculus; basal cell clear; nodus cen- tral; costal margin of forewings minutely spinose. Abdomen First abdominal segment in males containing tymbal organs; central dorsal sclerite modified to resemble a "bow tie." Second abdominal seg- ment produced anteriorly on each side into a small tymbal covering that leaves approximately two-thirds to three-fourths of the tymbal organ exposed; sternal sclerite produced into lateral bulges. Sexual Characteristics Ninth dorsal segment in males not prominently produced centrally, lateral margins produced into two upturned points; uncus withdrawable, notched both caudally and laterally (see Figure 9). Subgenital plate of female shallowly notched (Figure 9). Diagnostic Characters The adpressed pronotal margins and non parallel first and second crossveins in the forewings are primary diagnostic characters. Second- arily, small size, basically light coloration, and the relatively small eyes are helpful. Males are easily identified by the shape and extent of the tymbal covers and the central sclerite separating the opercula (Figure 9) . Figure 9. Beameria. A, dorsal view of male; B, ventral view of male abdomen; C, ventral view of terminal segments of female abdomen; D, caudal view of male abdomen showing uncus (after Davis, 1934); E, map showing distribution of the genus by state. Arrows point to diagnostic characters of the genus. Species illustrated is Beameria venosa. -69- -70- Distribution Beameria is apparently confined to America north of Mexico. It has been recorded in the literature from Texas, New Mexico, Arizona, Okla- homa, Kansas, Colorado, and Nebraska. Discussion Changes in morphology of the nymphs of four of the five nymphal in- stars of B. venosa are described in Beamer (1928) . Beameria venosa adults frequently inhabit high, dry, rocky hillsides or hilltops where sparse grass and occasional yucca make up the only vegetation (Beamer, 1928). Davis (1921b) also reports B. venosa as a grassland species living in desert grass. It has been reported singing from thistle (Davis, 1921b). I have personally captured only one specimen of this genus, a B. venosa singing in Juniperns sp. just south of Sedona, Arizona. There was sparse grass in the area. It is not unusual for grass or weed inhabiting cicadas to utilize a higher perch for singing if one is available. Altitudes recorded for specimens taken in Arizona fall in the range of 1,500 to 2,500 meters. The song of B. venosa is shrill but difficult to hear beyond a few meters. The light coloration of B. venosa makes it incon- spicuous among the dry grass it inhabits. Beamer (1928) records B. venosa as sluggish and not easily frightened into flight. He describes the nests as arranged serially in a single row along a stem. Each nest contains three to four white eggs and there may be a dozen or more nests in a series. Very little is known about Beameria wheeleri. It is also presumed to be a grassland species. Dates of capture on specimens of this genus I have examined range from June 9 to July 14. CHAPTER VIII Caaama Taxonomy Caaama Distant (1904b, p. 429) Type Species Caaama maura (Distant) (Distant, 1904b) = Proarna maura Distant Species The five species of Caaama reported from North America north of Mexico are C. aalifovnica Davis C. arepitans (Van Duzee) C. dissimilis (Distant) C. valvata (Uhler) C. variegata Davis Discriptive History The genus Caaama was described more completely than most North American genera. I have added additional features in the following de- scription, and Distant' s remarks are referred to in the appropriate -71- -72- sections. In 1919, Davis considered the genus as a whole, adding four species to the list of Caaama and providing a key to Cacaina identifica- tion. No new species have been described since that time. Description General Body Proportions Length of body 21.0 to 30.0 mm Expanse of forewings 64.0 to 83.0 mm Caaama are robust insects with the abdomen representing approximately one-half the body length. The length of the abdomen is less than two and one-half times the width of the mesonotum. Head Width of head, including eyes, much narrower than the width of the mesonotum; eyes in a line with or extending slightly beyond the anterior edge of the pronotum; vertex of epicranium horizontal, frons sloping or vertical, forming an obtuse to right angle with the dorsum of the clypeus; distance between lateral ocelli about the same to slightly less than dis- tance between lateral ocelli and eyes; clypeus moderately truncate, ex- tending only slightly beyond the supraantennal plates and giving the head a blocky appearance; dorsum of clypeus shorter than frons; "rostrum reaching or passing the posterior coxae" (Distant, 1904b). Thorax Pronotum ampliated posteriorly, strongly arched anteriorly, lateral carinae complete but minimal on the anterior half, lateral edges -73- smooth; length of pronotum shorter than mesonotum; "Mesonotum somewhat convexly gibbous" (Distant, 1904b); mesonotum obscuring central portion of metanotum; opercula in males large, "about half the length of abdomen above, broad, their apical margins convexly rounded, their lateral margins almost straight" (Distant, 1904b), overlapping medially. Legs Anterior femora with two prominent spines beneath; posterior mera short, sometimes blunt, usually equilateral. Wings Forewing venation is illustrated in Figure 10. Both "wings (ex- cepting base) hyaline . . . apical areas [of forewings] eight in number, the two lowermost small , subquadrangular" (Distant, 1904b); first and second crossveins may or may not be parallel; medial and cubital veins arising separately from the arculus; nodus central; costal margin of forewings not noticeably spinose, may have a few tiny spines proximal to body. Abdomen "Abdomen short, broad, convex above" (Distant, 1904b); first ab- dominal segment in males containing tymbal organs, central dorsal sclerite with two rounded lateral lobes (Figure 10) ; second dorsal segment in males produced anteriorly on each side into a complete tymbal cover; "lateral margins of the tympanal coverings subparallel to the abdominal margins" (Distant, 1904b); lateral bulge inconspicuous. Figure 10. Cacama. A, dorsal view of male; B, ventral view of male abdomen; C, ventral view of terminal segments of female abdomen; D, caudal view of male abdomen showing uncus (after Davis, 1919b); E, map showing distribution of genus by state. Arrows point to diagnostic characters of the genus. Species illustrated is Cacama valvata. -75- -^Xr? \ 5- -76- Sexual Characteristics Ninth dorsal segment of males rounded laterally, produced into a central spine dorsally; uncus withdrawable, simple (Figure 10). Sub- genital plate of female shallowly notched centrally, smooth, not sinuous (Figure 10). Diagnostic Characters Caoama is easily recognized by its stout gestalt. The combination of the mesonotum overlapping the metanotum and the narrow, blocky head will identify both males and females. In addition the abdomen is broadly rounded caudally. Distribution Caoama extends from Yucatan, Mexico, northward to the southwestern United States. Within the United States it has been captured in Texas, Oklahoma, New Mexico, Colorado, Arizona, Utah, Nevada, and Southern California. Discussion Caoama is the only cicada genus found north of Mexico that might be considered a mimic. Their black or nearly black, robust bodies super- ficially resemble bumble bees. They initiate flight by hovering away from a perch rather than jumping into flight. The behavior of Caoama when captured in a net alsp is reminiscent of a bumble bee. Live Caoama are marked with a light colored pruinosity usually not seen in museum specimens. Heath, Wilkin, and Heath (1972) showed that C. valvata from -77- Arizona extended activity in the sun by orienting the reflective surface of the white, pruinose venter toward the sun's rays thereby diminishing the rate of heat gain. I have consistently found peak activity in C. valvata and C. dissirrrllis to range between 8:00 AM and 1:00 PM mountain standard time. Beamer and Beamer (1930) reported a similar activity period for C. crepitans. No data are available on the other two American species found north of Mexico. In Arizona I have captured Caaama from the desert plant formations to the pinyon- juniper plant formation. Al- though Beamer and Beamer (1930) reported capturing C. valvata from a yucca, sagebrush, and cedar habitat, and again, from a "habitat of small cedars" and C. dissirnilis from palo verde, I have found the same two species almost always associated with some species of Opuntia. All other reports in the literature are from Opuntia. Caaama will sing from higher perches when these are available. I have observed them on barbed- wire fences and telephone poles. I cannot help but wonder if some Opuntia was not present in the habitats reported by Beamer and Beamer. Caaama valvata was observed to spend the night feeding near the base of clusters of the flat pads of prickley pear by Heath, Wilkin, and Heath (1972). Beamer and Beamer (1930) found that wetting nests of C. valvata laid in cane cactus or exposing the nests to a cold morning rain approxi- mately three months after egg laying precipitated the emergence of the nymphs. They concluded that moisture, and consequently reduced soil temperatures, would increase the survival of nymphs from arid, hot habitats. Caaama has been given the popular name "cactus dodger." The song of Caaama resembles the sound of a chain saw cutting logs. Caaama dissirnilis was described by Distant (1881) from Mexico. I have seen the type specimen in the British Museum and believe it to be a -78- different species from that commonly identified as C. dissimilis in the southwestern United States. Dr. Thomas Moore of the University of Michigan has a manuscript in preparation naming the U.S. species. Remarks on C. dissimilis given above will be pertinent to this new species when Dr. Moore's description appears. CHAPTER IX Ciaadetta Taxonomy Ciaadetta Kolenati (1857, p. 417) Type Species Ciaadetta montana (Scopoli) (Kolenati, 1857) = Ciaada montana Scopoli = Ciaada ovni (nee Linne) = Tettigonia montana (Scopoli) = Ciaada pygmea Olivier = Ciaada tibialis Latreille (nee Panzer) = Ciaada angliaa Samouelle = Ciaada haematodes Linne (nee Scopoli) = Ciaadetta Amyot (nonbinomial) = Tettigonia haematodes (Linn£) (nee Scopoli) = Tettigonia dimidiata Fabricius « Ciaada sohaefferi Graelin = Ciaada parvula Walker =■ Melampsalia. montana (Scopoli) = Cicada saxoniaa Hartwig = Tettigia montana (Scopoli) -79- -80- Species Four species and one named variety occur in North America north of Mexico. The species are C. calliope (Walker) C. camevona (Davis) C. kansa (Davis) C. texana (Davis) Alexander (unpublished) considers the geographical variety Cicadetta calliope flovidensis (Davis) a distinct species. Cicadetta calliope flovidensis is distinguishable by color and patterning. Descriptive History At least six generic names have been used for all or part of the genus Cicadetta. Metcalf (1963) catalogs the names and synonomies while Chen (1943) gives a brief history of the status of the names. They each come to different conclusions regarding the proper name. References to North American species prior to Metcalf (1963) use the generic name Melampsalta. In 1847, Amyot published descriptions of Melampsalta, Cicadetta, and Tettigetta in that order. Although he included the range of body lengths, the major part of the descriptions deals with color patterning and not anatomical features. In this sense each description resembles a species description and not a generic description. Amyot apparently intended these names as part of a monomial system of nomen- clature and meant to refer only to what we now consider single species. Kolenati (1857) picked up Amyot 's names and gave them subgeneric status using the species described by Amyot as the types and attributing the names to Amyot. In Kolenati 's work the names appear in the following -81- order: Cicadetta, Tettigetta, Melampsalta. Kolenati's descriptions are morphological. According to Metcalf (1963) Stal was the first to synonomize the three in 1861. He, however, recognized Amyot as the author and used the name Melampsalta. Since that time various authors have recognized the same synonomy. The favored name depends on whether Amyot or Kolenati is recognized as author. Other authors have attempted to separate por- tions of the genus into new genera, but most of these names have not been generally accepted. The current status rests on the argument that Amyot did not intend to describe part of a binomial name. The species de- scribed by Amyot already had valid specific names. According to article lie of the International Code of Zoological Nomenclature, a name does not become available unless the author consistently applied the principles of binomial nomenclature in the work in which the name is published. Since Amyot was proposing monomial names, the names cannot be attributed to him. Kolenati, therefore, becomes the author. The subgenera described by him constitute the establishment of the genus and Ciaadetta becomes the valid name. This is apparently the view taken by Metcalf and now accepted on a world-wide basis. I have consulted the descriptions of Amyot (1847), Kolenati (1857), Ortega (1957), and Kato (1961). The following description is intended to encompass only those species found in North America north of Mexico. Description General Body Proportions Length of body 12.0 to 20.0 mm Expanse of forewings 25.5 to 40.0 mm The abdomen represents more than one-half the body length. -82- Head Width of head, including eyes, subequal with the width of the meso- notum; eyes prominent, may or may not project laterally beyond the anterior angles of the pronotum; vertex of epicranium horizontal; frons sloping, forming a broad obtuse angle with the dorsum of the clypeus; vertex and clypeus centrally sulcate; dorsum of clypeus somewhat centrally depressed; distance between lateral ocelli about the same or narrower than distance between lateral ocelli and eyes; clypeus and supraantennal plates forming the more or less continuous sides of a broad triangle with the sides notched where the clypeus and supraantennal plates meet; dorsum of clypeus shorter than frons; rostrum reaching to or barely beyond the intermediate coxae. Thorax Pronotum strongly arched laterally, not strongly ampliated, but usually having continuous carinae where the notal and pleural regions meet, lateral margins smooth, posterior angles lobately dilated; length of pronotum shorter than mesonotum; posterior margins of metanotum com- pletely visible behind mesonotum; opercula in males well developed, separated, rounded. Legs Anterior femora with at least three distinct spines; a fourth, less developed, distal spine is usually present. Fosterior mera narrowly drawn out at the tip. -83- Wings Forewing venation is illustrated in Figure 11. Wings hyaline. First and second crossveins in the forewings perpendicular and usually parallel; medial and cubital veins coalescent where they arise from the arculus; nodus more or less central, may be slightly further from the base of the wing than from the apex; costal margin of forewing may have several very fine spines. Abdomen First abdominal segment in males containing tymbal organs, posterior margin of central dorsal sclerite concave centrally; anterior margin of second dorsal sclerite curved smoothly entad laterally behind the tymbal organs; lateral bulge on sternite well developed in both sexes; tymbal organs exposed. Sexual Characteristics The ninth dorsal segment of the males may or may not project into an acute point dorsally, posterior margin with a caudally projecting, ventral lobe, a third lobe may be present along the ventral margin; uncus retractable, short, bifurcated with the two parts diverging outward from a caudal view and the apices subacute, curved inwardly from a lateral view (Figure 11). Subgenital plate of female with a large simple, triangular notch extending nearly to the base of the sternite (Figure 11). Figure 11. Ciaadetta. A, dorsal view of male; B, ventral view of male abdomen; C, ventral view of terminal segments of female abdomen; D, lateral view of extended male pygofer, caudal view of uncus (after Davis, 1920); E, map showing distribu- tion of the genus by state. Open circle is a questionable report. Arrow points to the coalesced media and cubitus emerging together from the arculus. Species illustrated is C. kansa. -85- 6 -86- Diagnostic Characters The coalesced medial and cubital veins in the forewings emerging together from the apex of the basal cell will separate Cicadetta from all other genera found in North America north of Mexico. In the other genera in this region the medius and cubitus leave the arculus separately. Distribution Cicadetta is widely distributed throughout all the world's biogeo- graphic regions except the Neotropical. Within the Nearctic region it is found throughout the southeastern United States, as far west as eastern Colorado, and north to Nebraska, Iowa, Illinois, Ohio, and Virginia. Cicadetta camevona and C. texana have thus far been reported only from Texas. Cicadetta calliope floridensis is found in Florida and Georgia. Davis (1930) records C. kansa from Kansas, Colorado, Oklahoma, and Texas. Cicadetta calliope calliope is the most widely distributed species. It is found in all of the above states except Oklahoma. Additional state records are from Missouri, Arkansas, Louisiana, Mississippi, Alabama, Tennessee, and North Carolina. There is a doubtful report from New Jersey. There are no records from Indiana, Kentucky, South Carolina, or West Virginia, but part or all of these states fall within a more generalized distributional pattern, particularly if the Ohio designation is accurate. These four states represent likely extensions of the reported distribution. -87- Discussion Ciaadetta is the most widespread genus in the family Cicadidae. Several factors may influence the widespread dispersal of Ciaadetta, among which are the age of the genus, size of the insects, and the period of development. There are, at present, no known fossil Ciaadetta to give us a clue to the age of the genus. If, however, Ciaadetta does represent a single phylogenetic line, the wide distribution would seem to infer that it is a very old genus. The majority of Ciaadetta species are small. Beamer (1928) remarks on the effects of wind in lengthening the flight of C. calliope in Kansas. Because of the small size of the adults, wind may well be a factor in Ciaadetta dispersal. Myers (1929) suggests that the entire New Zealand cicada fauna derives from a single immigrant species of Ciaadetta. whether this invasion resulted from rafting, wind, or a combination is difficult to say. Most cicadas spend a lengthy immature period underground. Although some cicadas have received popular names such as "annual cicada" and a two year life cycle has been proposed frequently, the shortest documented life cycle of a cicada is the four year cycle of Ciaadetta calliope (Beamer, 1928). If a relatively short life cycle is characteristic of the genus, more generations of Ciaadetta have been available for dispersal than have been available among those cicada genera of equal age with a longer subterranean existence. The probable habitat of the species of Ciaadetta in North America is perennial grasses and weeds. Like other cicadas, they will utilize the higher perches of shrubs or trees when singing. Beamer (1928) studied C. calliope calliope in detail in Kansas. This species is abundant frequently in meadowlands as long as fires or serious flooding do not prevail. Females oviposit in live material and the eggs wither if the branch dies. Nests are placed in a single row on pithy stems. Matura- tion of the eggs takes about two months. The song of the males is audible for only a distance of a few meters. Adults are preyed upon extensively by both robber flies (Asilidae) and spiders. Eggs are parasitized by chalcids of the genus Syntomaspis . Cicadetta in North America are active as adults from late April to August. Beamer (1928) also observed the behavior of the nymphs in glass sided cages. Cells are generally about one inch long. If the host plant dies the cell may be extended for several inches as the nymph searches for a new host. Loose dirt is dug from the front of the cell with the forelegs. It is then packed into a ball between the forelegs and the postclypeus and sub- sequently carried to the rear of the cell. Beamer found nymphs in the field usually six to ten inches beneath the surface. A disturbed nymph will rear and prepare to fight the offender with its fore femora. Beamer described the morphology of the five nymphal instars of C. calliope in detail. CHAPTER X Clidoph leps Taxonomy Clidophleps Van Duzee (1915, p. 31) Type Species Cliodphleps distanti (Van Duzee) (Van Duzee, 1915) = Okanagana distanti Van Duzee = Okanagana pallida Van Duzee = Okanagana pallidas Van Duzee = Clidophleps pallida (Van Duzee) Species Seven species and one named variety of Clidophleps occur in North America north of Mexico. The species are C. beameri Davis C. blaisdelli (Uhler) C. distanti (Van Duzee) C. rotundifvons (Davis) C. tenuis Davis C. vagans Davis C. wvighti Davis There is one named variety of Clidophleps distanti. -89- -90- Descriptive History The original description of Van Duzee (1915) compares features of Clidophleps with similar features in Okanagana and Platypedia. A few diagnostic features are given. Simons (1954) keys and illustrates a generalized wing and the terminal abdominal segments of the males of the California species. No other general work on the genus has appeared, and no complete description has been written. Description General Body Proportions Length of body 19.0 to 26.5 mm Expanse of forewings 44.0 to 71.0 mm The abdomen represents approximately one-half the body length. In addition the long, slender body has a "bullet or torpedo-shaped" appearance. Head Width of head, including eyes, narrower than the mesonotum; eyes in a line with or slightly wider than the anterior angles of the pronotum; vertex of epicranium horizontal, centrally sulcate; frons steeply slanted to vertical, forming an obtuse to right angle with the dorsum of the clypeus; distance between lateral ocelli greater than distance between lateral ocelli and eyes; clypeus broadly rounded, extending beyond the supraantennal plates, centrally sulcate apically and ventrally; dorsum of clypeus about the same to slightly longer than frons; rostrum reaching intermediate coxae. -91- Thorax Pronotum steeply arched laterally; lateral carinae continuous but varying between minimal and ampliated on a species specific basis; lateral edges usually smooth, posterior angles dilated; length of pro- notum shorter than mesonotum; mesonotum with a raised striated surface located next to the base of the forewing when folded against the body; posterior margin of metanotum completely visible behind mesonotum; opercula in both sexes small, transverse, rounded, widely separated, not extending beyond the base of the abdomen. Legs Anterior femora with two prominent spines; posterior mera broadly triangular. Wings Forewing venation is illustrated in Figure 12. Wings hyaline, basal cell clear; first and second crossveins in forewings usually oblique and parallel; third marginal cell at least two-thirds the length of second ulnar cell; costal margin of the radial cell less than two and one-half times longer than the medial vein anterior to the first branch; radial cell of forewing frequently expanded; the transverse crossvein between MQ and Cu usually thickened; medial and cubital veins arising separately o from the arculus; the cubital vein with at least a slight arch; nodus central; costal margin of forewing with a few very minute spines. Figure 12. Clidophleps . A, dorsal view of male; B, ventral view of terminal segments of male abdomen; C, ventral view of terminal segments of female abdomen; D, lateral view of terminal male abdominal segments showing uncus in profile, dorsal view of uncus (after Simons, 1954); E, map showing distribution of the genus by state. Arrows point to diagnostic characters. Species illustrated is C. vagans. -93- -94- Abdomen First abdominal segment in males containing tymbal organs, central dorsal sclerite visible as a thin band centrally, turned outward laterally proximal to the tymbal organs (Figure 12) ; anterior margin of second dorsal sclerite turned outward forming a ribbon-like structure posterior to the tymbals; lateral bulge obvious; tymbal organs exposed. Sexual Characteristics Ninth dorsal segment of males rounded laterally, caudal margin con- cave dorsally; uncus stationary, not retractable, simple (Figure 12); hypandrium elongated. Subgenital plate of female broadly and doubly notched (Figure 12) . Diagnostic Characters Males can be identified by the exposed tymbals flanked posteriorly by the ridged anterior edge of the second abdominal tergite and the long unbranched portion of the medial vein in the forewing. Females can be identified by the combination of a visible metanotum, broadly rounded clypeus, complete carina formed by the lateral edge of the pronotum, and forewing characteristics. Distribution In North America north of Mexico, Clidophleps occurs in California and Arizona. Five species appear to be restricted to California. Clidophleps rotundifrons is found in Arizona. Clidophleps tenuis extends -95- into Lower California and C. astigma is known only from the Mexican side of the border in Baja or Lower California. Discussion An accessory stridulatory surface on the anterior, lateral portions of the mesonotum reaches its greatest development north of Mexico in the genus Clidophleps. Boulard (1976a) illustrates this structure in C. blaisdelli and C. vagans. The verification of two songs from the same individual was reported by Davis (1943) for Clidophleps beamevi from observations made by J. Beamer. The sound was characterized as starting "with a clicking, and then run into a rattle or whir, which is made by the drumming of the wings." The Beamers at first felt there were two species present until they identified both songs in a single individual. I have had a similar experience with Okanagana synodica (Say) and was further confused by two color forms which subsequently turned out to be a sexual dimorphism. A mesonotal stridulatory surface is present in four genera found in America north of Mexico. This feature further confirms the close phylogenetic relationship between Clidophleps, Okanagana, Okanagodes, and Tibicinoides . Little is known about the ecology of Clidophleps. They are active as adults from late May to early August. Most species seem to prefer a scrub or chaparral type habitat. They have been captured from the seashore to the mountains in California and from desert to mountain forest con- ditions. Clidophleps rotundifrons from Airzona has been taken at 1,100 meters from scrub oak and red mahonia by M. Kolner (1976 — personal com- munication) . Several species have been described as singing in a unified chorus normally initiated by the singing of a single individual. The -96- song can be stimulated artificially by the sound of an automobile engine (Beamer and Beamer, 1930). The song is usually of short duration making individuals difficult to locate. Beamer and Beamer (1930) reported C. distanti ovipositing in the twigs of a young orchard containing peach, plum, and citrus trees. They also found the same species associated with a vineyard. CHAPTER XI Cornuplura Taxonomy Cornuplura Davis (1944, p. 217) Type Species Cornuplura curvispinosa (Davis) (Davis, 1944) = Tibicen curvispinosa Davis Species One species of Cornuplura, C. nigroalbata (Davis), occurs in North America north of Mexico. Cornuplura rudis (Walker) was reported from Arizona by Uhler (1892) from a single fragmentary specimen, but that report now appears to be erroneous. Descriptive History Davis' (1944) description is in the nature of a comparison between Tibicen, Diceroprocta, and Cornuplura. No complete description of the genus has been written. -97- Description General Body Proportions Length of body 34.0 to 38.0 mm Expanse of forewings 95.0 to 102.0 mm The abdomen represents about one-half the body length. It may be slightly longer in males with the genitalia extended. Head Width of head, including eyes, broader than the mesonotum; eyes extending slightly beyond the anterior margin of the pronotum; vertex of epicranium horizontal, frons nearly vertical; distance between ocelli less than distance between lateral ocelli and eyes; clypeus moderately tumid, projecting beyond the supraantennal plates; dorsum of clypeus as long as frons; rostrum reaching just short of posterior coxae (in C, vudis it reaches the anterior portion of the coxae) . Thorax Pronotum ampliated laterally forming definite lateral carinae, lateral edges smooth, not toothed; length of pronotum shorter than meso- notum; mesonotum obscuring central portion of metanotum; opercula in males large, longitudinal, overlapping medially. Legs Anterior femora with two prominent spines beneath and the remnant of a third distal spine; posterior mera elongated, acute, with a slight inward curvature. -99- Wings Forewing venation is illustrated in Figure 13. Both wings hyaline; first and second crossveins in forewings oblique, parallel, may be very slightly infuscated; length of R, ,- between the first and second cross- veins less than R, , _ between the first crossvein and the ambient vein, 4+5 medial and cubital veins arising spearately from the arculus; nodus central, costal margin of the forewing may have a few very minute spines. Abdomen First abdominal segment in males containing tymbal organs, central dorsal sclerite with basically the same curvature as succeeding tergites; second dorsal segment in males produced anteriorly on each side into a complete tymbal cover, lateral bulge lacking. Sexual Characteristics Ninth dorsal segment of males rounded laterally, produced into a central spine dorsally and two spines extending from the ventral margin; uncus withdrawable, deeply cleft or bifurcated (Figure 13). Subgenital plate of female smoothly bilobed, eighth sternite visible beneath sub- genital plate, produced into two medial hooks (Figure 13). Diagnostic Characters Males can be distinguished by the two spines extending from the ventral margin of the pygofer. Females can be distinguished by hooks on the eighth sternite combined with a black basal cell in the forewings. Figure 13. Covnuvlura. A, dorsal view of male; B, ventral view of male abdomen; C, ventral and caudal views of terminal seg- ments of female abdomen. Caudal view shows hooks on eighth sternite lying under the subgenital plate. D, lateral and caudal views of terminal male abdominal segments (after Smith and Grossbeck, 1907). Lateral view shows ventral spines on extruded pygofer. E, map showing distribution of the genus north of Mexico. Arrows point to diagnostic characters. Species illustrated is C. nigvoalbata. -101- ,ry\y h^_1^2m i — $>. -102- Distribution Cornuplura has been reported in central Mexico from Jalisco, Colima, Vera Cruz, Moreles, and the Distrito Federal. North of Mexico it has been recorded only from Santa Cruz County, Arizona. Discussion The above description was written to include the male Cornuplura rudis in my possession. In C. rudis the ventral spine on the ninth dorsal segment of the males is much shorter and stouter than in C. nigroalbata. In general appearance Cornuplura resembles the parallel sided Tibioen found in the southwestern United States. It is, however, larger than species that make up this group of Tibicen. Species of Cornuplura have also been compared favorably with Tibioen plebeja, the type of the genus Tibioen. Davis (1944) places the genus Cornuplura between Tibioen and Diceroprocta. In almost all characteristics except male genitalia it agrees with Tibioen. The deeply cleft uncus is somewhat similar to Diceroprocta but is fused at the base. In C. rudis the uncus is simple for part of its length and then divides. In females the hooked eighth sternite is shared with some members of the genus Tibioen. This character should be viewed caudally. Little is known of the biology of C. nigroalbata. The type is a female captured from an oak on August 15, 1935. Four males and a female were captured near the type locality on July 12 and 13, 1940. On June 21, 1972, J.E. Heath captured a male on the mountainside overlooking Lago Pena Blanca, a few miles east of the type locale. Although this individual was captured singing on mountain mahogany, others were singing from black -103- oak in the general vicinity. The 1935 and 1940 specimens were also captured from "oaks." As far as I know, these are the only specimens taken. The animals were actively singing in mid afternoon (2:30-4:30 PM mountain standard time) from perches near the periphery of the host plant. They were widely scattered, solitary animals. The song was the loudest I have heard, although this may have been amplified by the nature of the small valley. The song also had a strong metallic quality. Experiments to determine thermal parameters of this species showed it required a mean body temperature of 18.1°C to fly. It stopped basking and moved into shade at a mean body temperature of 37.8°C and reached heat torpor at 44°C. Temperature measurements were made with a thermistor probe de- scribed by Heath and Adams (1969). I returned to the same locality ex- actly one year later but did not hear this species. Analysis of the years of capture indicates there is probably more than one brood of C. nigvoalbata in Santa Cruz County, Arizona. CHAPTER XII Dicevopvocta Taxonomy Dicevopvocta Stal (1870, p. 714) Type Species Dicevopvocta alacvis (Stal) (Still, 1870) = Cicada transversa Walker = Cicada alacvis Stal Species There are nineteen species and five named varieties of Dicevopvocta in America north of Mexico. A twentieth species D. bicosta has been reported from Florida, but the identification is in doubt (Davis, 1938; Mead, 1978 — personal communication). The species are D. apache (Davis) D. avizona (Davis) D. avevyi Davis D. azveca (Kirkaldy) D. beqvjievti (Davis) D. bibbyi Davis D. biconica (Walker) D. canes cens Davis D. cinctifeva (Uhler) D. delicata (Osborn) D. eugvaphica (Davis) D. knighti (Davis) D. mavevagans Davis D. olympusa (Walker) D. semicincta (Davis) D. swalei (Distant) -104- -105- D. texana (Davis) D. viridi fascia (Walker) D. vitripennis (Say) In addition there are two named varieties of D. ainctifera and one each of D. deliaata, D. serrricincta, and D. swalei. Descriptive History The generic name Dioeroproata appears in a key in Stal's Hemiptera Insularum Philippinarum. Two characters are given, one for males, one for females; however, neither will separate the genus as currently recog- nized. Dioeroproata was essentially ignored until Davis, in 1928, moved the United States species and three others into this genus. He added two more characters, but neither of these stand alone as diagnostic of the genus. A complete description of Dioeroproata has never been written. Description General Body Proportions If Dioeroproata biaosta is subsequently shown to occur in North America north of Mexico, it will be the largest Dioeroproata in the region with a body length circa 34 mm and a forewing expanse circa 102 mm. Dioeroproata biaonica from the Florida Keys approaches this size range. With the exception of the two species, D. bioosta and D. biaonica, body dimensions range as follows: Length of body 17.0 to 30.0 mm Expanse of fcrewings 52.0 5o 85.0 mm The abdomen represents approximately one-half the body length. -106- Head Width of head including eyes about as broad or broader than mesonotum; eyes projecting slightly beyond the anterior margin of the pronotum; ver- tex of epicranium horizontal, frons sloping vertically, sometimes con- tinuous with dorsum of clypeus, sometimes forming an obtuse angle with the dorsum of the clypeus; distance between ocelli less than distance between lateral ocelli and eyes; clypeus in a more or less continuous line with supraantennal plates, not projecting prominently, dorsum as long or longer than frons; rostrum reaching posterior coxae or beyond. Thorax Pronotum ampliated laterally forming definite lateral carinae, lateral edges smooth; length of pronotum shorter than mesonotum; meso- notum obscuring most of metanotum; opercula in males large, either rounded or triangular, meeting or nearly meeting centrally. Legs Anterior femora with two prominent spines beneath; posterior mera narrow and angulate. Wings Forewing venation is illustrated in Figure 14. Both wings hyaline, infuscated markings various. Davis (1928) gives the following forewing characteristic for Diaevovvoota, "... the first cross vein of the fore wing does not, as a rule, start as far back or near to the base of the wing from radius 3 as it does in Tibiaen.. " Length of R. , _ between the & 4+5 -107- first and second crossveins usually equal to or greater than R, _ between the first crossvein and the ambient vein; first and second crossveins usually parallel; medial and cubital veins arising separately from the arculus; nodus central; costal margin of forewings minutely spinose. (See discussion section for further elaboration of the above characters.) Abdomen First abdominal segment in males containing tymbal organs, central dorsal sclerite variable in shape and visibility; second dorsal segment in males produced anteriorly on each side into a complete tymbal cover; lateral bulge inconspicuous. Sexual Characteristics Ninth dorsal segment of males not produced into a central spine, lateral margins usually produced into two upturned points, uncus with- drawable, bifurcated with a dorsal projection (Figure 14). Subgenital plate of female usually "sinangulate at middle of apex and on each side very obtusely rounded sinuate" (Davis, 1928 translation of Still, 1870) (Figure 14) . Diagnostic Characters No single diagnostic character is consistent throughout the genus except the bifurcated, "wishbone shaped" uncus of the males. In most cases deviations from the general description are on an individual basis and not characteristic of a species as a whole. Both males and females can be identified by a combination of characters. The position of the Figure 14. Diaerovroota. A, dorsal view of male; B, ventral view of male abdomen; C, terminal segments of female venter; D, lateral view of terminal male segments, caudal view of uncus; E, map showing the distribution of the genus by- state. The report from New Jersey is questionable and is indicated by an open circle. Wisconsin records are un- verified. Arrows indicate diagnostic characters. Species illustrated is D. apache. -109- -110- first crossvein in the forewings and its relationship to the longitudinal veins and/or the sinuate subgenital plate will identify females. The position of the first crossvein of the forewings and/or the shape of the ninth dorsal segment will identify males without dissecting out the uncus. The ninth dorsal segment in males has two diagnostic characters, the lack of a central spine and the acute lateral lobes. Males have a complete tymbal cover. In size, Diaeroproota is larger than Paoarina, and United States species, with a few exceptions, are smaller than United States species of Tibicen. Distribution Diaeroproota extends from northern South America, where it has been recorded from Brazil, Guyana, and Venezuela, north throughout Central America, Mexico, the islands of the Carribean and into the United States. Within the United States, the genus extends along the Atlantic coast from New Jersey to the Florida Keys. Dioeroprocta is found in all states comprising the southern boundary of this country, from southern California to Florida. The range of Diaeroproota apaohe extends into southern Nevada, Utah, and Colorado, while D. eugraphioa is found from Texas north to southern Kansas. One species, Diaeroproota vitripennis , inhabits many of the midwestern states. It is recorded from Nebraska, Kansas, Oklahoma, Missouri, Arkansas, Illinois, Indiana, and the southern tip of Michigan in addition to more southerly states. Dr. Moore tells me it may also reach into southern Wisconsin (Moore, 1977, personal communication). -Ill- Discussion The variation in generic characters may be individual, confined to a single deme, or specific in nature. I have observed the following exceptions to the five morphological characters used to diagnose the genus. All specimens of Dicevoproota asteca I have seen lack the acutely pointed lateral lobes on the last dorsal segment of the males. This character is the source of the generic name. The lack of these acute lobes appears to be a species characteristic in D. azteoa. Specimens of Biaevopvocta ccrizona from the Chiracahua mountains, Arizona, have a central spine on the ninth dorsal segment of the males, whereas, para- types from the Santa Rita mountains, also in Arizona, lack this spine. I interpret the presence of the spine in the Chiracahua population as a local phenomenon. The sinuous posterior margin of the female subgenital plate is one of the original characteristics cited by Stal (1870) . The sinuations are present to some extent in almost all specimens of the genus I have seen; however, they occasionally may be reduced in an in- dividual specimen so that the plate appears smoothly bilobed. I have observed specimens of D. clumpusa like this, and Lawson (1920) pictures the subgenital plate of a female D. eugvaphioa from Kansas as smoothly bilobed. The last of the five diagnostic characters is the position of the first crossvein in the forewings. The position and cant of this vein is highly variable within the genus. It may be perpendicular to strongly oblique. Usually the first and second crossveins are parallel, but in an occasional individual, the first crossvein will be less oblique than the second. For this reason Diaer-oproata occurs twice in the key to the females. Wherever Davis mentions this character, it is always compared with the genus Tibicen. In an attempt to quantify the character so that -112- a comparison specimen of Tibiaen is not required, I measured the distance between the first and second crossveins versus the distance between the first crossvein and the ambient vein along R _. The result in ninety per cent of the measurements was an equal or greater length between the crossveins than between the first crossvein and the ambient vein. In similar measurements on Tibiaen the distance between the crossveins was always shorter than the distance between the ambient vein and the first crossvein. From 1916 when Van Duzee published his Check List of the Hemiptera of North America North of Mexico to 1928 when Davis separated out the Diaeroproata, this genus was considered part of the genus Tibiaen. The two genera appear to be closely related, and except for a general size differential north of Mexico and the five diagnostic characters mentioned above, they are difficult to separate. Exceptions to diagnostic charac- ters in Diaeroproata overlap the corresponding characters in Tibiaen. Internal structures revealed by X-rays confirm this basic similarity. Tibiaen is the dominant genus in the Eastern United States while Diaeroproata reaches its greatest diversity in the southern states west of the Mississippi river. Only five species of Diaeroproata occur in the southeast with fourteen additional species in the southwest from Texas to California. Diaeroproata continues to flourish farther south in what Metcalf (1946) calls the Caribbean region while the number of Tibiaen species drops to a handful. Ecologically it is difficult to characterize a genus this large and diverse. Different members of the genus have adapted to most plant types from grass to trees. Some, such as Diaerovroata knighti, seem restricted to one host plant while others, such as D. vivripennis and D. apaahe, in -113- addition to their endemic hosts, have adapted to various cultivated plants on which they occasionally have been considered pests. Davis (1928) cited D. vitripermis as a destructive pest of cotton and Brown and Eads (1967) cited D. apache as a pest of ornamental elms in southern California. The distribution of several members of the genus has been expanded by following stream or river courses. Dicevopvocta cinctifeva is found along such courses and D. apache, which is prevalent in the desert around Phoenix but absent at altitudes above the Pinyon-Juniper plant formation, follows the Colorado river through the Grand Canyon and thus occurs in extreme northern Arizona and southern Utah. Adult Dicevopvocta tend to be sedentary in their habits, singing from a con- tinuous perch rather than singing then flying like Magicicada. Dicevo- pvocta are preyed upon by birds, other insects, and small mammals. Davis (1924) records Evax intevvuptus , an asilid fly, attacking Dicevopvocta olympusa. Desert species of Dicevopvocta avoid severe predation by being active during midday periods when ambient temperatures are beyond the thermal tolerances of their predators. Heath and Wilkin (1970) docu- mented this behavior for D. apache. Additional data indicate a similar activity pattern for D. semicincta. Dicevopvocta apache is preyed upon in the Phoenix desert by a cicada killer wasp. Cranford (1978, personal communication) found heteromyid rodents feeding extensively on D. apache adults in northern Arizona and southern Utah. An analysis of fecal pellets showed cicada parts comprised up to sixty-five per cent of the fecal mass of Dipodomys spectabilis and D. ovdii. CHAPTER XIII Magicicada Taxonomy Magicicada Davis (1925), p. 43) Type Species Magicicada savtendecim (Linne) (Davis, 1925) = Cicada sevtendecim Linne = Tettigonia septendecim (Linne) = Tettigenia cos talis Fabricius = Tibicen septendecim (Linne) = Tibicina septendecim (Linne) Species There are six species of Magicicada in America north of Mexico. The species are M. cassini (Fisher) M. septendecim (Linne) M. septendecula Alexander and Moore M. tredecassini Alexander and Moore M. tvedecim (Walsh and Riley) M. tvedecula Alexander and Moore -1H ■115- Descrlptive History Davis1 (1925) description is in the nature of a comparison of features primarily between Magicacada septendeaim and Tibioina haematodes (Scopoli) , the type species of the genus Tibioina in which M. septendeaim was at that time placed. Tibioina does not occur in North America. Alexander and Moore (1962) give diagnostic characters to separate Magioioada from other eastern North American cicadas. Description General Body Proportions Length of body 19.0 to 33.0 mm Expanse of forewings 55.0 to 83.0 mm The abdomen is greater than one-half the body length in both sexes. Head Width of head, including eyes, subequal with the width of the mesonotum; "head including eyes is distinctly wider than the front edge of the pro- notum and distinctly narrower than the rear edge of the pronotum" (Alexander and Moore, 1962). Epicranium broadly rounded from a horizon- tal position at the base of the vertex to a nearly vertical position where the frons joins the clypeus; frons forming a slightly obtuse angle emarginate with the dorsum of the clypeus; distance between lateral ocelli less than distance between lateral ocelli and eyes; clypeus tri- angular, extending well beyond the supraantennal plates; length of dorsum of clypeus about the same as length of frons; rostrum reaching posterior -116- Thorax Pronotum adpressed laterally except at posterior angles, lacking continuous lateral carinae. Length of pronotum shorter than mesonotum; posterior margin of metanotum completely visible behind mesonotum; opercula in males broadly rounded, not extending beyond the second abdominal sternite. Legs Anterior femora with two or three prominent spines; posterior mera sharply elongate. Wings Forewing venation is illustrated in Figure 15. Both wings hyaline; first and second crossveins in the forewings oblique, nearly parallel, and frequently infuscated; medial and cubital veins arising separately from the arculus; basal cell infuscated; nodus central; costal margin of forewing minutely spinose. Abdomen First abdominal segment in males containing tymbal organs; central dorsal sclerite rounded laterally, somewhat sinuous along posterior margin (Figure 15) ; anterior margin of second dorsal sclerite turned smoothly entad posterior to tymbals; lateral bulge present; tymbal organs exposed. Figure 15. Magicicada. A, dorsum of male; B, venter of male; C, terminal segments of the female venter; D, caudal view of male abdomen showing uncus; E, distribution map of the genus by state and province. Small dots are used for the small northeastern states and the panhandle of Florida. Arrows point to the location of diagnostic characters. Species illustrated is M. sevtendeaula. -118- L.JSrJJ : i*Yi. "_• O #* Klf^k *«SSL •" n I WVl — -119- Sexual Characteristics Ninth dorsal segment in males prominently produced into an acuminate central spine; 9th segment bears small mediad projections caudally; uncus withdrawable, bifurcated, "viewed caudally it has the form of two sclerites extending downward from the anal tube, encircling the penis, and widening below it into two triangular processes which taper to acute apices. The penis is usually strongly protruded from between the two parts of the uncus and possesses terminally two very characteristic little sclerites . . . whose rounded margins are strongly serrate" (Lawson, 1920) (Figure 15). Subgenital plate of female with a single, large broad "incision posteriorly which reaches over one-half the distance to the base" (Lawson, 1920) (Figure 15). Diagnostic Characters Males can be distinguished by a combination of the lack of tymbal covers, retractable uncus, and medial and cubital veins arising separately from the arculus. Females can be distinguished by a combination of the visible metanotum, adpressed pronotum lacking complete lateral carinae, and the triangular clypeus. The dorsal thorax in both sexes is black without patterning. Distribution Magidicada is distributed throughout the eastern United States with one record from Quebec, Canada, reported by Alexander and Moore (1962). Within the United States they have been found in all the states east of the Mississippi River except New Hampshire and Maine. Their southern -120- limit in the east is the panhandle of Florida. West of the Mississippi River the range of Magicicada extends to eastern Texas, Oklahoma, Kansas, and Nebraska; the range is bounded by Iowa on the north and Louisiana on the south. Discussion Because of their long life cycle, periodicity, and enormous syn- chronous emergences, Magicicada have attracted as much attention as all the other genera found north of Mexico combined. Magicicada consists of three sets of sibling species. Each set contains a thirteen year species and an, as yet, inseparable seventeen year species. The three seventeen year species have the longest known insect life cycle. Early settlers recorded the large emergences of these cicadas and Magicicada septendecim is an original Linnaean species. A smaller "dwarf" variety was recognized in the 1830's, but it was so difficult for early naturalists to accept the concept of two long-lived synchronized species that the second species, M. cassini, was not named until 1851. The thirteen and seventeen year "decim" siblings were separated in the 1860's. Almost one hundred years passed before Alexander and Moore (1962) described the third set of siblings and also separated M. tredecassini as a separate thirteen year species. Magicicada inhabits the eastern deciduous forest. Although specimens have been recorded each year, there are apparently eighteen successful broods, thirteen with seventeen year life cycles and five with thirteen year life cycles (Alexander and Moore, 1962). Three species occur in at least thirteen of the eighteen broods. Although the distribution of the -121- thirteen and seventeen year broods overlaps, the thirteen year broods represent the more southerly parts of the distribution of the genus, and the seventeen year broods comprise the most northerly portions of the distribution except for a southwestern extension of M. cassini (Brood IV) into eastern Texas. The presence of only M. ea.ssi.ni in the southwestern extremes of the range and only M. septendeoim in the northern extremes of the range combined with the upland, xeric, habitat preferences of the "deoula" siblings led Alexander and Moore (1962) to propose a southwestern origin for the "cassini" siblings, a south-central origin for the "deaim" ancestor, and a southeastern origin for "decula." They also feel that the present distribution is the result of at least two periods of brood formation with Pleistocene glaciation involved in the most recent period. Individual broods of cicadas may also overlap, but the overlapping broods do not occur as adults in consecutive years. Consecutive broods are frequently contiguous in distribution, and a small amount of gene flow from one brood to the next may occur through stragglers emerging out of synchrony and joining an active emergence of another brood. When two or three species emerge together, they tend to divide the available habitat both behaviorally and ecologically. Alexander and Moore (1962) recorded maximal chorusing of M. tvedeairn in midmorning, M. tvedeaula in midday, and M. tvedeoassini in midaf ternoon. Dybas and Davis (1962) found a definite preponderance of M. septsndeoim in upland areas of oak-hickory and M. cassini in an adjacent floodplain area in a study of Brood XIII in northern Illinois. Dybas and Lloyd (1962), in the same study area, reported overlapping of the species on the inter- mediate slope and also on a grove of young, previously uninhabited, ash growing in a recently cleared area nearby. Magicicada septendecula was -122- not present. While " cassini" and "decim" appear somewhat catholic in their host plants "decula" is apparently restricted to hickory, Cory a spp. (J.E. Heath, 1978, personal communication). The most potent isolating mechanism is the song. Magicicada cassini and M. tvedecassini have evolved a highly elaborate synchronous chorus in which all male members sing in unison followed by a short burst of flight. J.E. Heath (1967) found the synchronous chorus occurred when males reached a body temperature of 30°C or more. The "deaula" chorus appears less synchronous and the "decim" species do not sing in synchrony, but males of all six species follow the song with flight. The auditory stimulus of the song combined with the visual stimulus of flight tend to aggregate both males and females of the same species in the same location. In more solitary cicadas, it is the song of the individual male that attracts a mate. These males tend to be more sedentary in behavior. In Magi cicada it is the chorus that attracts both sexes to a common location. J.E. Heath (1978, personal communication) has observed an isolated M. sevien- decim calling without the accompanying flight. The attraction of a Magicicada chorus is not limited to cicadas. Both the movement of the flight and the sound of the song are powerful attractants for predators, especially birds. There are numerous reports of the annihilation of small emergences prior to reproduction. Most cicadas are wary. Many are protectively patterned or colored. Magicicada are both conspicuous and docile. Lloyd and Dybas (1966b) have labeled them "predator-foolhardy." This suggests that the group behavior of the congregational chorus has been selected over the incompatible secretive behavior of predator avoidance (Lloyd and Dybas, 1966b). In order for this to occur, large populations of the cicadas must emerge synchronously. -123- No one knows how Magiaicada "count" the thirteen or seventeen years between emergences, but J.E. Heath (1968) showed that emergence is thermally synchronized. Emergence occurs when soil temperatures 20 cm below the surface reach 18°C. The other essential parameter is population density. The synchronous emergence of more than one species decreases the predator pressure on each individual species. Although density varies from place to place and generation to generation, millions of Magiaicada can emerge within the space of a few miles. Dybas and Davis (1962) found a density of 1,500,000 cicadas per acre in a floodplain habitat in northern Illinois. They calculated the biomass of this same population at 1,913 to 3,685 kg/ha (1,707 to 3,288 lbs/acre), the highest mean biomass per unit of habitat recorded for a terrestrial animal under natural conditions. Their net average annual productivity of cicada protoplasm, 112 to 216 kg/ha (100-193 lbs/acre), is comparable to con- trolled beef production. With such high population densities verified, are there any controls on Magiaicada populations? Predator satiation apparently occurs quickly in a large Magiaicada emergence, but the long term effects of an increase in predator populations have disappeared before the next generation of cicadas appears. Predator pressure probably eliminates the possibility of consecutive broods developing in the same locality. Lloyd and Dybas (1966a) suggested that moles are important predators of late instar nymphs. They also cited evidence that larvae of the predacious burrowing fly, Coenomyia pallida Say, will attack nymphal cicadas. Green muscardine disease will infect mature nymphs. The fungus Massospora aicadina Peck attacks the adults and is apparently the only specific organism that remains viable during the seventeen years between emergences. Lloyd and -124- Dybas (1966a) conclude that "food and space" (i.e., the scarcity of feeding sites) may be important in limiting Magicioada populations. Magiaioada have been implicated as severe pests in orchards, par- ticularly on apples. The pruning caused by oviposition usually en- courages new growth in the natural forest habitat. In a cultivated orchard, however, young trees can be killed by a large emergence. There is also some evidence that large nymphal populations underground may reduce production of fruit. CHAPTER XIV Neocicada Taxonomy Neooicada Kato (1932, p. 168) Type Species Neocicada hievoglyphica (Say) (Kato, 1932) = Cicada hievoglyphica Say = Cicada chavactevea Germar = Cicada sexguttata Walker = Tettigia hievoglyphica (Say) = Tettigia chavactevea (Germar) = Tettigia sexguttata (Walker) = Tibicen hievoglyphica (Say) Species There are two species and one named variety of Neocicada in America north of Mexico. The species are .V. hievoglyphica (Say) N. chisos (Davis) Neocicada hievoglyphica johannis is found principally in peninsular Florida. Alexander (unpublished) does not consider johannis a good subspecies . -125- -126- Descriptive History Kato's (1932) description is short and incomplete. Although Kato's monograph is in Japanese, the description is given in English, a language that appears somewhat unfamiliar to the author. Kato was unaware of N. chisos and its relationship to N. hieroglyphica. He stated that the species (N. hieroglyphioa) previously belonged to the genus Cicada, but that the characters differ from Cicada ovni, the genotype of Cicada. He did not say how they differ, however. Davis (1925) stated .V. hieroglyphica is allied closely to Cicada ovni. The two genera are zoogeographically separated. External morphological differences are compared in the fol- lowing discussion. Description General Body Proportions Length of body 22.0 to 27.0 mm Expanse of forewings 54.0 to 68.0 mm In male specimens the abdomen is elongated and greater than one-half the body length. In females, the abdomen represents approximately one- half the body length. Head Width of head, including eyes subequal with the width of the meso- notum; eyes projecting laterally beyond the anterior angles of the pro- notum; "Head with the front deflected before the eyes" (Kato, 1932), making the profile slightly emarginate at the juncture of the clypeus and the epicranium; width between ocelli less than width between lateral -127- ocelli and eyes; clypeus and supraantennal plates in a more or less broadly rounded, continuous curve; clypeus not prominently produced anterioraly; dorsum of clypeus subequal in length to frons; rostrum reaching at least the posterior margins of the metathoracic coxae. Thorax Pronotum ampliated laterally forming definite lateral carinae, lateral edges smooth, not toothed; length of pronotum shorter than meso- notum; "lateral margins obliquely narrowed anteriorly . . . posterior lateral lobe somewhat developed" (Kato, 1932); mesonotum obscuring cen- tral portion of metanotum; opercula in males small, rounded, widely separated, and not extending beyond the base of the abdomen; opercula in females similar to those of males. Legs Anterior femora usually with three distinct spines, distal spine occasionally lacking, rarely armed with four spines; posterior mera slender, elongated. Forewing venation is illustrated in Figure 16. Both wings hyaline; first, second, third, and fourth crossveins infuscated; infuscated dots on longitudinal veins near the ambient vein; first and second cross vei oblique, virtually parallel; medial and cubital veins arising separately from the arculus; basal cell clear; nodus central; costal margin of forewings with a few very minute spines. 08 -128- Abdomen First abdominal segment in males containing tymbal organs, central dorsal sclerite with basically the same curvature as succeeding tergites; second dorsal sclerite in males produced anteriorly on each side into an incomplete, rounded tymbal cover (Figure 16) that leaves the tymbal organ partially exposed laterally; bulges marking the lateral ends of the second sternite are located ventrally on the insect. Abdominal cuticle thin, may be transluscent , particularly in males. Sexual Characteristics Ninth dorsal segment of males slightly produced centrally, rounded laterally; uncus withdrawable, simple, shallowly notched caudally (Figure 16), not notched laterally. Subgenital plate of female projecting slightly centrally, projecting region notched medially* (Figure 16). Diagnostic Characters Males can be easily identified by the rounded partial tymbal covers. Both males and females can be identified by the combination of the meso- notum partially covering the metanotum, first and second cross veins parallel, and infuscated markings on the longitudinal veins near the ambient vein. The usual diagnostic character used to identify Neoaiaada is the translucent abdomen. While this is very evident in male speci- mens, it is not very apparent in dried females. Quesada also has a somewhat translucent abdomen. Therefore, I prefer the above characters to identify members of this genus. *I have not been able to verify this character in a female N. chisos. Figure 16. Neooiaada. A, dorsal view of male; B, ventral view of male abdomen; C, terminal segments of female venter; D, caudal view of male abdomen showing uncus; E, map showing the distribution of the genus by state. Small dots indicate smaller eastern states. Arrows point to diagnostic charac- ters. Species illustrated is N. hieroglyphica. -130- ./-I -131- Distribution Neocicada occurs from Long Island, New York, southward along the east coast of the United States to Florida. It inhabits all of the gulf coast states and extends up the Mississippi valley to Missouri and Illinois. Its western range extends from Tamaulipas, Mexico, to southeastern Kansas. Discussion Through the courtesy of Dr. Michel Boulard of the Museum National d'Histoire Naturelle, Paris, I have in my possession two male specimens of Cicada orni, the type species of the genus Cicada. I do not know the full range of characters in Cicada, but from a comparison of these specimens with our North American species, it appears that Neocicada has a relationship to Cicada similar to that of Dicevoprocta to Tibicen. It does not appear closely related to any of the other genera found in North America north of Mexico. I have not explored a relationship with more tropical American genera. There are also no closely related fossils in North America. Outside of the obvious size, color, and pattern dif- ferences which usually distinguish species, there are morphological dif- ferences in both forewing venation and the structure of the male uncus between Cicada and Neocicada. In the forewing, R0 is proportionately longer in Neocicada and is subsequently bisected more evenly by the first crossvein than in Cicada ovni . In C. cvni the section of R anterior to the first crossvein is short as in Tibicen. In Neocicada the medial and cubital veins are very close together where they arise from the arculus (Figure 15). In Cicada the degree of separation is again similar to Tibicen (Figure 23). The male uncus in Neocicada is simple, but shallowly -132- notched. In Cicada it is deeply cleft into two distinct forks or prongs. These morphological differences appear to justify Kato's separation of our North American species into their own genus on a morphological as well as zoogeographical basis. In north central Florida, Neooioada hieroglyph-Lea is the first cicada to emerge each year, appearing around mid April (T.J. Walker, 1976, personal communication) . The songs of scattered individuals may be heard into early October. In the more northerly parts of its range, the appearance of adults is much more restricted. Beamer (1928) recorded imagos in Kansas from June 7 to August 7. Dates reported for N. ohisos are in June and July. Neooioada hievoglyphica are most active at dawn and dusk, but on warm summer days, individuals may be heard singing throughout the day and early evening. I have even heard them in the middle of the night in mid-summer when they were perched near a street lamp. The preferred host plants for Neooioada appear to be oaks. Davis (1916) reported them from the "Pine Barrens" of New Jersey. In the mixed pine/oak forests of the south, they sing from both types of trees. Beamer (1928) noted that they are only found in Kansas in regions with sandy soil. The relationship between soil characteristics and cicadas has net been explored but may be very important in determining the dis- tribution of genera and species. Beamer (1928) observed the eggs are laid in dead twigs with three eggs per nest. He also described the five nymphal instars. Neooioada are cryptically colored. Beamer (1928) stated these basically straw and green insects with disruptive black markings "blend almost perfectly with the lichen-covered trunks of the oak trees on which they are found making individuals very difficult to find." I have had similar experiences in Florida. Both species are wary and -133- difficult to capture and observe (Beamer, 1928; Davis, 1932). The cant of the wings on resting Neooicada is flatter and less tent-like than the other genera found north of Mexico. The thin cuticle and largely vacuous abdomen of males makes Neocicada light in weight for its size. Weights of live male N. hievoglyphiaa range from 215 mg to 240 mg. CHAPTER XV Neoplatypedia Taxonomy Neoplatypedia Davis (1920, p. 121) Type Species Neoplatypedia ampliata (Van Duzee) (Davis, 1920) = Platypedia ampliata Van Duzee Species Both species of Neoplatypedia occur in North America north of Mexico. They are N. ampliata (Van Duzee) N. constvicta Davis Descriptive History Davis' (1920) description compares features of Neoplatypedia that differ from corresponding characters in Platypedia. No complete de- scription has been written. Davis included a key to both species in his 1920 paper. Since both species occur in California, a complete key to the genus is found in Simons (1954) . -134- -135- Description General Body Proportions Length of body 15.0 to 19.0 mm Expanse of forewings 38.0 to 44.0 mm The abdomen is greater than one-half the body length. The following general characters cited by Uhler (1888a) in his description of Platypedia also apply to Neoplatypedia , "Elongate, acutely tapering posteriorly, with a sub-carinate ridge on the tergum, extending from near the base to beyond the middle." Davis (1920) remarks, "When the insect is turned over, the wings, if closed, are seen to cover about the apical third of the abdomen." Neoplatypedia are black, with the exception of the following body regions which are normally pale: part of the supraantennal plates, a median line and the posterior edge of the pronotum, the propleura, the posterior edge of the mesonotum including the posterior half of the cruciform elevation, the posterior edge of the metanotum. Head Width of head, including eyes, slightly narrower than the width of the mesonotum; eyes may or may not project beyond the anterior angles of the pronotum; vertex of epicranium horizontal; frons gently sloping forming a broad obtuse angle with the dorsum of the clypeus; vertex and clypeus centrally sulcate; distance between lateral ocelli narrower than distance between lateral ocelli and eyes; clypeus strongly convex, nar- rowing anteriorly, prominently protruding beyond the supraantennal plates, longer than frons; rostrum reaching beyond the intermediate -136- Thorax Pronotum strongly arched laterally, not ampliated, but having con- tinuous carinae where the notal and pleural regions meet, lateral margins smooth, sides parallel except at dilated posterior angles; length of pronotum shorter than mesonotum; posterior margin of metanotum completely visible behind mesonotum; opercula not developed. Legs Anterior femora armed with two prominent spines, sometimes showing the rudiments of a third distal spine; posterior mera long, triangular. Wings Forewing venation is illustrated in Figure 17. Wings hyaline; first and second crossveins in the forewing parallel; "costal vein is strongly expanded and bent beyond the middle of the radial cell" (Davis, 1920), expansion extending both anteriorly and ventrally; radial cell long, ex- tending more than one-half the length of the forewing; U„ nearly tri- angular; medial and cubital veins arising separately from the arculus; cubital vein arched; nodus of forewing about two-thirds out on the costal margin; costal margin of forewing may have a few minute spines; marginal cells seven in number. Abdomen Tymbal organs of males rudimentary; first abdominal tergite in both sexes with the anterior margin somewhat indented dorso-laterally forming a small gap between the abdomen and the metathorax, reduced to a narrow -137- band centrally, frequently covered by the metanotum; laterally a colored membrane is visible between the thorax and abdomen when the wings are spread. Second dorsal sclerite resembles succeeding tergites, not specialized; lateral bulge on sternite may be inconspicuous. Sexual Characteristics Ninth dorsal segment of males rounded laterally, caudal margin slightly concave dorsally; uncus stationary, not retractable, simple, "remarkably long and upturned at the extremity" (Davis, 1920) (Figure 17); hypandrium extremely elongate; subgenital plate of female with a simple deep notch nearly reaching the base of the segment (Figure 17). The terminal segments in both sexes are narrow and acutely tapering. Diagnostic Characters Neoplatypedia is the only genus found in North America north of Mexico with seven marginal cells in the forewings. The other genera have eight. The position of the nodus about two-thirds out on the costal margin of the forewing separates Neoplatypedia from ail other genera found north of Mexico except Platypedia. Distribution Neoplatypedia is known only from North America north of Mexico. Both species occur in California. Neoplatypedia ampliata is reported from Oregon, and N. oonstviota is recorded from Arizona, Colorado, Idaho, and Utah. Figure 17. Neoplatypedia. A, dorsal view of male; B, venter of male; C, terminal segments of female venter; D, lateral view of terminal male segments and dorsal view of uncus (after Davis, 1920); E, map showing distribution of the genus by state. Arrows indicate diagnostic characters. Species illustrated is N. aonstricta. -139- -140- Discussion Neoplatypedia is most closely related to the genus Platypedia from which it can be distinguished by having forewings with seven marginal cells instead of eight and a greater expansion and bend in the costal margin. In Platypedia the venter is completely visible when the wings are closed, but in Neoplatypedia, the closed wings meet and obscure the apical third. The distal tip of the uncus is turned upward in Neoplatypedia and not in Platypedia. As in Platypedia, the male tymbal organ is no longer functional in Neoplatypedia. Sounds are made by clicking or rubbing the costal margins of the forewing together beneath the body or by "banging" these margins against the substrate on which the insect sits. The costal margin is expanded ventrally at the point at which it bends, bringing the two fore- wings into close proximity. Since the sound is made by both sexes, it may function as a congregating device rather than a specific mating call or, as suggested by Dugdale and Fleming (1969) for Amphipsalta, the two-way communication may "speed the coming together of the sexes." The reasons for considering the lack of a functional tymbal organ a secondary loss rather than a primitive characteristic are discussed under the genus Platypedia. Neoplatypedia appears to be derived from Platypedia. Like Platypedia it shares a number of characteristics with the okanaganoid genera, Okanagana, Okanagodes , Tibiainoides, and Clidophleps . Among these are the visible metanotum and the nonretrac table uncus. Wing expansion can be traced from the narrow wings of Okanagana, through Clidophleps and Platypedia, to Neoplatypedia which exhibits the greatest modifications of the forewings. -141- Very little is known of the ecology of Neoplatypedia. Adults are active from April through midsummer. Neoplatypedia oonstvieta is re- corded from sagebrush (Artemesia sp.) (Davis, 1927; Fautin, 1946). It is an important midsummer invertebrate component of the northern desert shrub biome in Western Utah, providing a primary source of food for lizards (Fautin, 1946) . Fautin further stated that they "tend to remain close to the main branches of the sagebrush." Similar shaded, somewhat cooler, microhabitats are inhabited by Dicevopvoata during midday on mesquite (Heath and Wilkin, 1970). In Colorado, N, aonstviata was col- lected at about 1,850 meters (Davis, 1921b). The same article describes the song as a "zip, zip, zip, zip continued for a long time." CHAPTER XVI Okanagana Taxonomy Okanagana Distant (1905c, p. 23) Type Species Okanagana rimosa (Say) (Distant, 1905e) = Cicada rimosa Say = Tibicen rimosa (Say) Species There are fifty-two named species Okanagana in America north of Mexico. frons belongs in the genus Clidophleps and four named varieties of A fifty-third species 0. rotundi- (M.S. Heath, 1976). The species 0. albibasalis Wymere 0. annulata Davis 0. arboraria Wymere 0. arctostaphylae Van Duzee 0. aurora Davis 0. balli Davis 0. bella Davis 0. canadensis (Provancher) 0. oanesoens Van Duzee 0. oruentifera (Uhler) 0. davisi Simons 0. ferrugomaculata Davis 0. formosa Davis 0. fratercula Davis 0. fumipennis Davis 0. gibbera Davis 0. hesperia (Uhler) 0. hirsuta Davis -142- -143- 0. Vuvida Davis 0. luteobasalis Davis 0. magnified Davis 0. mariposa Davis 0. napa Davis 0. nigriviridis Davis 0. nigrodorsata Davis 0. noveboracensis (Emmons) 0. oacidentalis (Walker) 0. opaaipennis Davis 0. oregona Davis 0. ornata Van Duzee 0. vallidula Davis 0. rimosa (Say) G. rubrooaudata Davis 0. rubrovenosa Davis 0. sahaefferi Davis 0. simulata Davis 0. sperata Van Duzee 0. striatipes (Haldeman) 0. sugdeni Davis 0. synodica (Say) 0. tannevi Davis 0. triangulata Davis 0. tristis Van Duzee 0. ^jnai'nata Van Duzee 0. utahensis Davis 0. vanduzeei Distant 0. vandykei Van Duzee 0. Venus ta Davis 0. villosa Davis 0. viridis Davis 0. wymevei Davis 0. vakimaensis Davis In addition there is one named variety each of 0. tvistis, 0. synodica, 0. rimesa, and 0. mariposa. Okanagana striatipes variety beamevi equals 0. hespevia (M.S. Heath, 1976). An additional species, 0. georgi, de- scribed by Heath (M.S. 1976) is unpublished. Descriptive History Distant 's (1905a) description of Okanagana covers a number of important features that will be referred to in the appropriate places in the follow- ing description. However, because of the limited number of species available to Distant, several of his features are now not consistent -144- throughout the genus as it is currently recognized. Van Duzee in A Preliminary Review of the West Coast Cicadidae (1915) wrote a key to twenty species of Okanagana . Davis (1919a) treated the genus in depth. He added the nonretractable status of the male uncus as a generic feature. Davis covered thirty-five species in his remarks. Two of the species covered by Van Duzee and Davis have subsequently been moved to the genus Tibicinoides , and one covered by Davis belongs in the genus Clidophlsps . Simons covered thirty- five species of Okanagana in The Cicadas of California (1954), and M.S. Heath (1976) treated thirteen species from Arizona. Specimens of a fourteenth species from Arizona, 0. schaefferi, have subsequently been discovered. Description General Body Proportions Length of body 15.0 to 35.0 mm Expanse of forewings 37.0 to 90.0 mm The length of the abdomen is equal to or greater than one-half the body length. Head Width of head, including eyes, narrower than the mesonotum; eyes in a line with or slightly narrower than the anterior angles of the pro- notum; vertex of epicranium horizontal, frons steeply slanted to vertical, forming an obtuse to right angle with the dorsum of the clypeus; "vertex centrally sulcate" (Distant, 1905c); distance between lateral ocelli about the same to slightly greater than distance between lateral ocelli -145- and eyes; clypeus triangular, extending well beyond the supraantennal plates; "face more or less centrally sulcate" (Distant, 1905c); dorsum of clypeus usually longer than frons, but this ratio is species specific; "rostrum reaching the intermediate coxae" (Distant, 1905c). Thorax Pronotum ampliated laterally forming definite lateral carinae, lateral edges smooth or jagged (irregularly toothed), "anterior angles in a line with eyes . . . posterior angles dilated" (Distant, 1905c); length of pronotum shorter than mesonotum; mesonotum frequently striated where the base of the forewing folds against the body; posterior margin of metanotum completely visible behind mesonotum; opercula in both sexes small, transverse, rounded, widely separated, not extending beyond the base of the abdomen. Legs Anterior femora with two prominent spines; posterior mera broadly triangular (Figure 18) . Wings Forewing venation is illustrated in Figure 18. Wings hyaline, frosty, opaque, or partially opaque, rarely more than slightly infuscated except within the basal cell; first and second crossveins in forewing usually oblique and parallel; marginal cells of forewing at least two- thirds the length of the corresponding ulnar cells; costal margin of radial cell at least two and one-half times longer than the medial vein -146- anterior to the first branch; "basal cell [of forewing] about or almost twice as long as broad" (Distant, 1905c); medial and cubital veins arising separately from the arculus; nodus central; costal margin of forewing usually with a few very minute spines, occasionally spinose proximal to the body. Abdomen First abdominal segment in males containing tymbal organs, central dorsal sclerite, when visible, somewhat sinuous posteriorly, central portion frequently obscured by posterior margin of metanotum; anterior margin of second dorsal sclerite turned outward forming a ribbon-like structure posterior to the tymbals; lateral bulge obvious; tymbal organs exposed. Sexual Characteristics Ninth dorsal segment of males rounded laterally, posterior margin concave dorsally; uncus stationary, not retractable, simple (Figure 18); hypandrium elongated. Subgenital plate of female either singly or doubly notched (Figure 18) . Diagnostic Characters A combination of characters is necessary to distinguish Okanagana. The ampliated pronotum, exposed tymbals, nonretractable uncus, and forewing venation will identify males. The visible metanotum, forewing characteristics, and ampliated pronotum will distinguish females. The distinctly triangular rather than broadly rounded clypeus is a secondary diagnostic feature for both sexes. Figure 18. Okanagana. A, dorsal view of male; B, venter of male; C, terminal segments of female venter; D, lateral view of terminal male segments and dorsal view of uncus (after Davis, 1919a); Em, map showing the distribution of the genus by state and province. Small dots are used for the smaller New England states. The open circles in New Jersey and Virginia are doubtful reports. Although no Okanagana have been reported from Saskatchewan, the species found in Alberta and Manitoba is presumed to be there and is indicated by an open triangle. Arrows indicate the location of diagnostic characters. Species illustrated is 0. belZa. -148- [V-M At i VI •"> -149- Distribution Although several species of Okanagana have been described since Davis wrote his paper on cicada distribution in 1930, his delineation of the range of Okanagana north of Mexico remains accurate. One species, 0. aurantiaaa, is known only from Baja, California. The currently re- corded distribution of the remaining species is confined to North America, north of Mexico. Okanagana extends across southern Canada and the northern half of the United States from coast to coast. In the northeastern United States its range extends southward to Pennsylvania, Ohio, Indiana, and Illinois with one possible location reported from Virginia. Okanagana has been recorded in every state west of the Mississippi River except Oklahoma and Louisiana. One species, 0. viridis , has been reported from Mississippi, Tennessee, Arkansas, and eastern Texas. Okanagana is apparently absent from the remaining southeastern states. Discussion Okanagana is the western counterpart of Tibiaen. While species of Tibia en have proliferated in the eastern United States with relatively few species invading the southwestern states, Okanagana reaches its greatest diversity west of the Rocky Mountains with relatively few species present in the northeastern regions of the North American continental range of the Cicadidae. Simons (1954) records the greatest diversity in a single state with thirty-five species of Okanagana in California. Okanagana does not occur in tropical or low desert habitats. In Arizona, I have found Okanagana from the lower altitudinal limits of the Pinyon to the Hudsonian life zones of Merriam (1890) at altitudes of 915 to -150- 3,200 meters. The latter, a female 0. rubrocaudata captured on a small aspen on Mount Humphries, is the highest reported altitudinal record for a cicada. The species of Okanagana apparently extend their range south- ward in the western United States by following the mountain ranges. It is difficult to characterize the habitat of a genus as large as Okanagana. Okanagana adults are found in grass, shrub, and arboreal habitats. Each species is associated with one or more distinct vegeta- tion types which in turn are dependent on climate, altitude, and edaphic features for their distribution. M.S. Heath (1976) proposes that 0. bella, 0. synodioa, and 0. magnifica are key faunal indicator species of pine, steppe, and Pinyon-Juniper plant formations, respectively, in Arizona. Many species of Okanagana appear restricted to a single host plant. Okanagana rubvovenosa, 0. arctostaphylae, and 0. opacipennis all inhabit only manzanita, and each exhibits a protective coloration that blends with the dull red color of the host plant stems. Some species appear more catholic in their taste. Simons (1954) reports 0. vanduzeei ovipositing "in a variety of plants including goldenrod, sage, Bacahavis, and Pinus spp." The behavior and activity of Okanagana appear to be more influenced by thermal parameters of their environment than by size or morphological features. Thus, those species living in environments where the body heat generated by long flights would thermally stress the insects tend to be congregating species, inhabiting a restricted portion of their potential habitat. Those species living in environments where they are unlikely to encounter thermal stress tend to disperse throughout the available habitat and become solitary species. Okanagana utahensis, 0. magnifica, 0. synodioa, probably 0. fumipennis, 0. rubrovenosa, 0. maviposa, and -151- 0. geovgi (nomen nudum) are all congregating species, while 0. bella, 0. rubrocaudata, and 0. hesperia are solitary. The body temperature for heat torpor circa 43.5°C, appears remarkably consistent throughout the genus, but other thermal parameters appear linear with altitude. J.E. Heath et al. (1971) and M.S. Heath (1972) record minimum temperatures for flight and the temperatures at which basking ceases and individual cicadas seek the shelter of shaded locations for four species. Shade seeking temperatures range between 31.8°C and 37.6°C for Okanagana. Adult Okanagana live between one and two months, with females apparently outliving males. A major cause of death is predation by birds. Myers (1929) lists several bird predators of Okanagana. Soper, Shewell, and Tyrrell (19 76) report on a sarcophagid parasite of 0. vimosa apparently attracted by the song of the male cicada. Soper (1963) records a fungus, Massosvora levispora Soper, attacking the same species. The genus Okanagana appears closely related to Clidovhleps , Tibicinoides , and Okanagodes. Okanagana share a number of character- istics with Platypedia and Neoplatypedia, implying a more distant rela- tionship with these two genera. CHAPTER XVII Okanagodes Taxonomy Okanagodes Davis (1919a, p. 221) Type Species Okanagodes gracilis Davis (1919a) Species Both species in this genus occur in America north of Mexico. The species are 0. gracilis Davis 0. terlingua Davis There is one named variety or subspecies of 0. gracilis. Descriptive History Davis' (1919a) description is brief and concerned basically with the general habitus of the genus. Features are compared with Gkanagana. No complete description has been written and no comparisons are made with the other two closely allied genera. -152- -153- Description General Body Proportions Length of body 16.5 to 23.0 mm Expanse of forewings 42.0 to 58.0 mm The abdomen represents one-half the body length. Okanagodes are slim, parallel sided cicadas. Known species range in color from green to brownish, with some demes a light beige or straw color. Head Width of head, including eyes, narrower than the mesonotum; eyes prominent and may extend slightly beyond the anterior angles of the pronotum; vertex of epicranium horizontal, centrally sulcate; frons slanted, forming an obtuse angle with the dorsum of the clypeus; dis- tance between lateral ocelli about the same or greater than distance between lateral ocelli and eyes; ocelli large, ruby red; clypeus steeply rounded, swollen, protruding prominently beyond the supraantennal plates, length about one and one-half times the length of the frons; rostrum reaching intermediate coxae. Thorax Pronotum constricted, adpressed laterally except at posterior angles, sides more or less parallel, lacking distinct lateral carinae; length cf pronotum shorter than mesonotum; mesonotum striated where base of forewing folds against the body; posterior margin of metanotum com- pletely visible behind metanotum; opercuia small, rounded, widely separated, not extending beyond the base of the abdomen. -154- Legs Anterior femora usually armed with two spines, although poor develop- ment of one or both spines seems to be a common anomaly in this genus. Posterior mera broad, somewhat rounded triangles. Wings Forewing venation is illustrated in Figure 19. Wings hyaline. First crossvein in forewing nearly perpendicular; second crossvein slightly oblique; first and second crossveins not parallel; ratio of costal margin of radial cell to the unbranched portion of the medial wein 2:1; marginal cells of forewing at least two-thirds the length of the corresponding ulnar cells, e.g., M to U • medial and cubital veins arising separately from the arculus; nodus central; costal margin of forewing with a few very minute spines. Abdomen First abdominal segment in males containing tymbal organs, posterior margin of central dorsal sclerite sinuous; anterior margin of second dorsal sclerite curved smoothly entad laterally behind the tymbal organs; lateral bulge well developed; tymbal organs exposed. Sexual Characteristics Ninth dorsal segment of males rounded laterally, posterior margin may or may not be concave dorsally; uncus stationary, not retractable, Figure 19. Gkanagodes . A, dorsal view of male; B, ventral view of male abdomen; C, terminal segments of female venter; D, lateral view of terminal male segments and dorsal view of uncus (after Simons, 1954); E, map showing the distribu- tion of the genus by state. Arrows indicate the location of diagnostic characters. Species illustrated is 0. gvaaili -156- -157- simple (Figure 19); hypandrium elongated. Subgenital plate of female broadly and doubly notched (Figure 19). Diagnostic Characters The extremely produced, steeply rounded clypeus and relatively shallow frons will identify Okangodes. Secondarily, the large ruby red ocelli and forewing are helpful characteristics. Distribution Okana.god.es gracilis extends into Lower California; otherwise, Okanagodes is known only from North America north of Mexico. Okanagodes gracilis is reported from Utah, Arizona, California, and Nevada. Okanagodes terlingua is known only from Texas. Discussion Davis (1919a) gives the following characteristics to distinguish Okanagodes from Okanagana, "... the pronotum is much narrower behind the eyes. . . . The body is slim with the sides more parallel than in any known species of Okanagana.1' Tibicinoides and Clidophlevs are also closely related to Okanagodes. Tibicinoides most closely approaches Okanagodes in the prominence and shape of the clypeus, but the short marginal cells in the forewings and the short unbranched section of the medial vein will in Tibicinoides clearly distinguish these two genera. The wing venation of Okanagodes lies intermediate between Okanagana. and Clidovhlevs . The unbranched portion of the medial vein in the forewing is longer proportionally than in most Okavxigana but shorter than most -158- Clidopkelps . In Ckanagana Cu is relatively straight as it is in Okanagodes terlingvs. In Clidovkleps Cu is arched. It is also arched in Okanagodes gracilis. Okanagodes have an accessory stridulatory surface on the anterior, lateral portions of the mesonotum similar to that found in the three related genera above. Beamer and Beamer (1930) reported that, when approached, Okanagodes will cease the normal intermittant "Z' Z' Z' . . . song or change to a more broken one." It is possible the more broken sound may be made by stridulation rather than the tymbal organs. The species of Okanagodes occur primarily on low-lying desert vegetation. They are adaptively colored, with the green forms preferring green stems, and the pale tan or straw forms occurring "in a habitat which looks to be almost entirely dry and dead" (Beamer and Beamer, 1930). Sage is apparently a common host, but singing males have been captured from many kinds of desert vegetation, grass, weeds, and even bare rock. They seldom fly when approached, probably because of the excessive ambient temperatures of their environment. The body heat generated by flight would quickly raise the internal body temperature to the point of heat torpor. A torporous animal would fall to the unprotected, hot, desert floor and experience thermal death. Like Dioerovrocta apache, Okanagodes gracilis are active when ambient temperatures are between 40° and 50°C. They are able to avoid severe predation by being active when predators are not. The only predator reported for Okanagodes gracilis is a bird, Geococcvx aalifornianus (Less.) (Myers, 1929). CHAPTER XVIII Pacarina Taxonomy Pacarina Distant (1905a, p. 314) Type Species Pacarina puella (Distant, 1905a) = Pacarina signifera (Walker) = Cicada signifera Walker Species The type species Pacarina puelta is the only described species that occurs in North America north of Mexico. Descriptive History Distant (1905a) bases his description on general body proportions, head characteristics, pronotal characters, tympanal coverings, opercula, anterior femora, and forewing characters. His remarks will be referred to in the appropriate sections. Description General Body Proportions Length of body 13.0 to 14.0 mm Expanse of forewings 34.5 to 41.5 mm •159- -160- In addition, Distant (1905a) gives the length of the abdomen as "about as long as the space between the apex of head and base of cruciform ele- vation," i.e., the abdomen represents approximately one-half the body length. Head Width of head, including eyes, broader than the mesonotum; eyes projecting laterally beyond the anterior angles of pronotum, appearing somewhat stalked; epicranium in a continuous gentle slope with the dorsum of the clypeus; width between ocelli less than width between lateral ocelli and eyes; clypeus and supra antennal plates rounded; dorsum of clypeus shorter than frons; rostrum reaching posterior coxae. United States specimens exhibit a sharp color demarcation between a dark dorsum and light venter. This line occurs just posterior to the anterior edge of the venter on the "face." Thorax Pronotum strongly arched laterally; lateral carinae continuous but minimal; lateral edges smooth, "slightly sinuous," with "posterior angles moderately lobately produced." Length of pronotum shorter than length of mesonotum; mesonotum obscuring most of metanotum; opercula in males large, broadly rounded, meeting or nearly meeting centrally. Legs Distant (1905a) states the "anterior femora armed with two strong spines beneath." United States specimens frequently have a third smaller -161- spine posterior to the larger distal spine. The posterior mera are narrow and angulate. Wings Forewing venation is illustrated in Figure 20. Both wings hyaline; infuscated markings various; first crossvein perpendicular, second cross- vein slightly oblique, first and second crossveins not parallel; medial and cubital veins arising separately from the arculus; basal cell clear; nodus central; costal margin of forewings spinose. Abdomen First abdominal segment in males containing tymbal organs, central dorsal sclerite modified to resemble a "bow tie." Second abdominal seg- ment produced anteriorly on each side into a triangular tymbal cover; covers concave medially exposing tympanal cavities; sternal sclerite produced into lateral bulges. Sexual Characteristics Ninth dorsal segment in males slightly produced centrally, produced region setaceous, lateral margins produced into two upturned points; uncus withdrawable, bifurcated, notched laterally (Figure 20). Seventh sternite of female shallowly notched, Figure 20. Diagnostic Characters The prominent eyes projecting laterally beyond the anterior edges of the pronotum combined with the small size and abrupt facial color Figure 20. Pacarina. A, dorsal view of male; B, ventral view of male abdomen; C, terminal segments of female venter; D, lateral view of terminal male segments and caudal view of male abdomen showing uncus; E, face showing color pattern; F, map showing the distribution of the genus by state. Arrows indicate diagnostic characters. Species illustrated is P. puella. -163- -164- change will distinguish this genus from all other American genera north of Mexico. This is the only genus in this region with triangular tymbal covers in the males. The nonparallel status of the first and second crossveins in the forewings is a secondary diagnostic character. Distribution The range of the genus Faoca"tna extends from Central America north- ward into the United States. Within the United States it has been re- corded in the literature from Louisiana, Texas, Oklahoma, and Arizona. I have also seen specimens from New Mexico. Discussion Very little is known about the biology of Pacarina. Davis (1917) mentioned that it was captured on Pvosopis glandulosa, mesquite, at Gillette, Texas. Beamer and Beamer (1930) recorded a capture from "cedar" near Ashfork, Arizona. Cedar is frequently used as a common name for the plant genus Junzperus . Collection dates on specimens I have seen range from May through mid August. Wing markings of Paoavina collected within the United States vary from immaculate to highly infuscated markings on all the crossveins at the bases of the marginal cells and en portions of the longitudinal veins surrounding the marginal cells. Thoracic notal markings also vary widely. Both the ecological notes and the diverse wing and notal markings make me suspect that the current species Paoavina pnelta is in reality a complex of two or mors species. CHAPTER IXX Platypedia Taxonomy Platypedia Uhler (1888a, p. 23) Type Species Platypedia aveolata (Uhler) (Distant, 1905d) = Cicada aveolata Uhler Species There are twenty-three described species of Platypedia, twenty- two of which have been reported from North America north of Mexico. They are P. af finis Davis P. apevta Van Duzee P. aveolata (Uhler) P. balli Davis P. bavbata Davis P. bermavdinoensis Davis P. faloata Davis P. gressitti Kato P. laticapitata Davis P. latipennis Davis P. mavivosa Davis P. middlekauffi Simons P. minor Uhler P. mohavensis Davis P. putnami (Uhler) P. vufipes Davis P. saotti Davis P. sinilis Davis P. sylvestevi Simons P. tomentosa Davis P. usingevi Simons P. vand.uzeei Davis There are four subspecies of P. putnami and one of P. mchavensis. -165- -166- Descriptive History Uhler's (1888a) description is the most complete original description of any of our American genera north of Mexico. Only two species were known to Uhler when he described the genus. He subsequently added a third the same year (Uhler, 1888b). Van Duzee (1915) added three more species and wrote a key to the genus as then known. He also added a generalized statement about the color patterning found in the genus. Davis (1920) added four more species and three varieties to the list of Platypedia in an in-depth treatment of the genus. He synonomized two of the known species. Davis added three additional generic morphological features. Simons (1953) named three species and rearranged the status of several others. In 1954, he keyed eighteen species known from California and listed their locations. Simons omitted one species described from California specimens. He may not have been aware of Kato's 1932 Monograph of Cicadidae written in Japanese in which P. gvess'itti is described. It is possible that P. gvessitti may be synonomous with a species covered by Simons. Description General Body Proportions Length of body 13.5 to 23.0 mm Expanse of forewings 34.0 to 59.0 mm The abdomen is greater than one-half the body length. Uhler (1888a) adds the following about the general appearance, "Elongate, acutely tapering posteriorly, with a sub-carinate ridge on the tergum, extending from near the base to beyond the middle; wing covers when at rest almost -167- vertical." Platypedia are black insects with normally the following pale markings: "sides of the face, supra-antennal plates in part, median line and hind edge of the pronotum, hind margin of the metanotum in- cluding the posterior one-half of the elevated X [of the mesonotum], the costal nervure as far as the node and the propleura superiorly" (Van Duzee, 1915) . Head Width of head, including eyes, subequal with width of the mesonotum; eyes may project laterally slightly beyond the anterior angles of the pronotum; vertex of epicranium horizontal; frons gently sloping forming a broad obtuse angle with the dorsum of the clypeus; vertex centrally sulcate; "the anterior ocellus placed in a longitudinal groove, which later is continued upon the tumid front [i.e., clypeus]" (Uhler, 1888a); distance between lateral ocelli slightly narrower than distance between lateral ocelli and eyes; clypeus "quite prominent, strongly convex; exterior cheeks long and narrow; supra-antennal plates narrow, thick, bounded on each side with a notch" (Uhler, 1888a); clypeus longer than frons; rostrum reaching the posterior margin of the intermediate coxae or beyond. Uhler (1888a) adds, "Head bluntly triangular, hirsute." Thorax "Pronotum short . . . with the dorsal surface feebly convex . . . , the lateral margins almost straight , with the anterior angles feebly reflexed, and the posterior angles narrowly, but abruptly turned up" (Uhler, 1888a). Pronotum strongly arched laterally, not ampliated, but -168- having small, continuous carinae where the notal and pleural regions join; lateral edges smooth; length of pronotum shorter than length of mesonotum; posterior margin of metanotum completely visible behind mesonotum; opercula not developed. Legs "Anterior femora short and stout, swollen in the middle" (Uhler, 1888a), armed with two prominent spines, sometimes showing the rudiments of a third distal spine; posterior mera broadly triangular. Wings Forewing venation is illustrated in Figure 21. Wings hyaline. First and second crossveins may or may not be parallel. "Wing covers [i.e., forewings] wide, strongly bowed on the costal margin, the areoles large and mostly wide, basal areole oblong, the radial areole occupying more than one-half the length of the wing-cover, the second ulnar areole short, wide, almost triangular; the apical areoles narrow, and the third, fourth, and sixth of equal length, with their inner tip triangular, while the inner end of the second, fifth, and seventh is truncated; wings [i.e., hind wings] narrow, not reaching as far as the tip of the discoidal areole of the hemelytra, with the anal-flaps broadly rounded, and separated by a deep emargination from the other member of the wing" (Uhler, 1888a). Medial and cubital veins arising separately from the arculus; cubital vein arched; nodus of forewing about two-thirds out on the costal margin; costal margin of forewings with at least a few minute spines; eight marginal cells. -169- Abdomen "Sonorus valves [i.e., tymbal organs] of the males rudimentary, inconspicuous" (Uhler, 1888a). First abdominal tergite in both sexes with the anterior margin indented dorso-laterally forming a gap between the abdomen and the metathorax, reduced to a narrow band centrally, frequently covered in part by the metanotum; laterally a colored membrane is visible between the thorax and abdomen when the wings are spread. Second dorsal sclerite resembles succeeding tergites, not specialized; united first and second sternite may or may not be well developed (lateral bulge) . Sexual Characteristics Ninth dorsal segment of males rounded laterally, caudal margin slightly concave dorsally; uncus stationary, not retractable, simple (Figure 21); hypandrium extremely elongate; subgenital plate of female with a simple deep notch (Figure 21) . The terminal segments in both sexes are "narrow and compressed, acutely tapering" (Uhler, 1888a). Diagnostic Characters Both male and female PZatypedia can be distinguished by a combination of the position of the nodus and eight marginal cells in the forewing. The nodus is not located centrally, but lies about two-thirds out on the costal margin. Figure 21. Platypedia. A, dorsal view of male; B, ventral view of male abdomen; C, terminal segments of female venter; D, lateral view of terminal male segments and dorsal view of uncus (after Davis, 1920); E, map showing the distribution of the genus by state and province. Arrows indicate diagnostic characters. Species illustrated is P. putnami lutea. -171- -172- Distribution One species of Platypedia, P. australis Davis, is known only from Nuevo Leon, Mexico. The remaining species are restricted to the western United States and Canada. Davis (1930) records P. areolata from British Columbia. Within the United States, Platypedia are recorded from Wash- ington, Oregon, Idaho, Montana, Wyoming, South Dakota, Nebraska, Colorado, New Mexico, Arizona, Utah, Nevada, California, and western Texas. A fossil Platypedia, P. primigenia Cockerell, is recorded from Miocene deposits at Florissant, Colorado. Discussion Members of the genus Platypedia lack a functional tymbal organ and, therefore, do not produce sound in the manner normally associated with cicadas. They do, however, possess the auditory "mirrors" found in cicadas. Both sexes of Platypedia produce a clicking sound with the forewings. Simons (1954) feels this sound is made by rubbing the fore- wings together. Dr. Thomas Moore (1975, personal communication), of the University of Michigan, calls Platypedia and Neoplatypedia "wing bangers.' He apparently feels that some species may produce sound by beating the wings against the substrate on which they are perched. The specialized costal margin of the forewings seems to indicate that the sound is pro- duced with that margin rather than clicking the hind margin over the ridge formed where the resting wing sits against the mesonotum. The mesonotum lacks the even striations found in Clidcphleps, Okanagodes, TibiainoideSy and some Okanagana. The upper surface of the ridge, how- ever, is irregular in many species. A slow motion photographic analysis -173- of Platypedia in the act of sound production is needed to determine exactly how the sounds are made. Several writers have in the past considered Platypedia and the re- lated genus Neoplatypedia primitive because of the rudimentary nature of the tymbal organs. I am inclined to agree with Simons (1954) when he says, "In the genus Platypedia the tympana are so reduced they no longer function as sounding organs" (italics mine) . Two lines of evidence sup- port this conclusion. Other Auchenorrhyncha have fully developed tymbal organs and tymbal muscles for the production of sound (Ossiannilsson, 1949; Pringle, 1954). The lack of a functional tymbal organ has also been discovered in African cicadas of the genus Ydiella (Boulard, 1973a) and Lamotialna (Boulard, 1975a) . Ydiella gilloni Boulard bears a stridulatory surface on the anal margin of the forewing and the costal margin of the hind wing (Boulard, 1973b). The African genera and the two North American genera, Platypedia and Neoplatypedia, have other mor- phological characters that relate them to genera within their own geographical regions. If a rudimentary tymbal organ is an indication of a primitive state, it would be difficult to explain present zoogeo- graphical distribution without invoking the parallel evolution of nearly identical sound producing tymbal organs, an unlikely hypothesis at best. I, therefore, feel that the rudimentary tymbal organ in Platypedia and Neoplatypedia represents a distant departure from an ancestral North American cicada rather than a close relationship with a primitive ancestor. Van Duzee (1915) remarked, "approaching Platypedia in its expanded elytra" in his original description of the genus Clidophleps. While the nodus remains central in Clidophleps, the radial cell in the forewing is -174- expanded and the costal margin in some species is strongly arched resembling the shape in some of the lesser arched species of Platypedia. In both Clidophleps and Platypedia, the cubital vein in the forewing is arched. The length of the medial vein prior to the first branch also resembles that character in Clidophleps . Davis (1920) remarked, "In Platypedia, as in Clidophleps, Okanagana, Okanagodes, and Tibieinoides the metanotum is conspicuous behind the mesonotum, and the uncus cannot be withdrawn into the abdomen." Platypedia is obviously most closely related to Neoplatypedia, from which it can be distinguished by having eight marginal cells in the f orewings , whereas Neoplatypedia has only seven marginal cells. The above remarks, however, indicate a secondary relationship of these two genera with the okanaganoid group. Like the okanaganoid genera, Platypedia reaches its greatest diversity in California with at least eighteen species occurring in that state. Platypedia is one of the larger genera of cicadas found in America north of Mexico. As such, different species have invaded a variety of habitats. They are reported from the California seacoast to elevations as high as 2,750 meters, and from desert shrubs to stream- side trees. Plavypedia adults are active from March to late July. Several species are very setose. It would be interesting to know if this "hair" has any insulating value to the individual. Platypedia do not fly readily. Platypedia putnami lutea drops to the ground when approached (Davis, 1943), a reaction similar to the death feint of Tibioinoides mevaedita. The only known predators of Platypedia are birds (Myers, 1929). Simons (1954) states that ?. minor and P. aveolata have been implicated in oviposition damage to economic plants in Northern California. -175- Platypedia is one of two modern North American genera documented in the fossil record. A nearly complete specimen of PZaiypedia pvimigenia was found in the Miocene deposits at Florissant, Colorado. Cooper (1941) stated this fossil "is in striking agreement" proportionally with P. putnanrt. It varies in details of venation. Another fossil, Lithoaiaada perita Cockerell, from the same deposits exhibits a forewing radial cell extending beyond the middle of the wing and may be related to the modern genus Platypedia. CHAPTER XX Quesada Taxonomy Quesada Distant (1905b, p. 478) Type Species Quesada gigas (Olivier) (Distant, 1905b) = Ciaada gigas Olivier = Ciaada triupsilon Walker = Cicada senans Walker = Ciaada aonsonans Walker = Ciaada vibrans Walker = Tympanoterpes sihilatvix Berg = Tympanoterpes gigas (Olivier) Species The type species Quesada gigas is the only representative of this genus that occurs in North America north of Mexico. Descriptive History Distant' s (1905b) description covers the major body regions; however, several additional features may be added to the characterization of Quesada in North America north of Mexico. ■176- -177- Dascription General Body Proportions The following ranges are based on specimens in my possession and photographs in Davis (1944). Length of body 29.0 to 45.0 mm Expanse of wings 95.0 to 120.0 mm In addition, Distant (1905b) indicates that the body is broad and robust and that the abdomen represents about one-half the body length. Head Width of head, including eyes, about as wide as the mesonotum. Distant (1905b) gives the following length comparison — length of head "about as long as pronotum without its posterior margin." Eyes con- spicuous, projecting laterally beyond the anterior edge of the pronotum; slope of epicranium emarginate where it joins the clypeus; width between ocelli less than width between lateral ocelli and eyes; supraantennal plates triangular; clypeus rounded; dorsum of clypeus longer than frons; "rostrum reaching base of posterior coxae." Thorax Pronotum strongly arched laterally; lateral carina present; anterior half of lateral edges jagged or irregularly toothed; "posterior angles moderately dilated." Length of pronotum shorter than length of mesonotum; mesonotum obscuring most of metanotum. "Metasternum centrally elevated, the process posterirly triangularly produced between the posterior coxae" (Distant, 1905b). Opercula in males small, widely separated, and -178- not extended beyond the base of the abdomen; opercula in females similar to those of males. Legs Anterior femora with two prominent spines beneath, sometimes a minute third spine posterior to the larger distal spine. Posterior mera elongated triangles. Wings Forewing venation is illustrated in Figure 22. Both wings hyaline, first and second crossveins of forewings slightly infuscated. The fore- wing is "long, somewhat narrow, greatest breadth not quite one-third of length" (Distant, 1905b). First and second crossveins oblique, vir- tually parallel; medial and cubital veins arising separately from the arculus; basal cell half opaque, half clear, "almost as broad as long"; nodus central; costal margin of forewings minutely spinose. Abdomen First abdominal segment in males containing tymbal organ; central dorsal sclerite reduced to a thin band medially. Anterior margin of second dorsal sclerite turned outward forming a ribbon-like structure posterior to the tymbals with a small lateral triangular projection; tymbal organ exposed; sternal sclerite not prominently bulged. Sexual Characteristics Ninth dorsal segment of males produced centrally, rounded laterally; uncus withdrawable, bifurcated with a central dorsal projection (see Figure 22. Quesada. A, dorsal view of male; B, ventral view of male abdomen; C, terminal segments of female venter; D, caudal view of male abdomen showing uncus; E, map showing the dis- tribution of the genus north of Mexico. Arrows indicate diagnostic characters. Species illustrated is Q. gigas. -180- \ ./ h T7 WTi^ns^rw^^n -181- Figure 22), not notched laterally. Subgenital plate of female with a small central notch, not bilobed (Figure 22). Diagnostic Characters The short, definitely triangular head with its prominent, laterally projecting eyes and the strongly arched pronotum with the irrepularly serrated lateral margins will identify this genus. The "ribbon-like" projection of the second abdominal tergite in the males and the shape of the subgenital plate in the females are also characteristic. Distribution The genus Quesada extends from southern Texas to Argentina north of a line drawn between Buenos Aires and Mendoza. In Texas, it has been recorded from Starr, Hildalgo, Cameron, Bexar, Nueces, and Bee counties. Discussion Myers (1929) and Davis (1944) summarize most of the literature on Quesada gig as . Davis points out that owing to its remarkable north-south distribution of some 6,500 kilometers, Quesada gigas is the only cicada found north of Mexico that is active in the adult form somewhere in its range every month of the year. In southern Texas, adults have been recorded from May to October. Quesada is arboreal and apparently eclectic in its choice of trees. In Texas, it has been taken from live oaks and mesquite. It sings chiefly at dawn and dusk but may also be active on warm, moonlit nights. It frequently occurs in broods and sings in chorus. An individual starts -182- singing with one or two tentative croaks. These are repeated by its neighbors. After this brief "warm-up" the entire area will resound with a loud, shrill, unison cry that has been likened to the whistle of a "first-rate locomotive." Because of its size, sound, and habits, Quesada gigas has acquired a number of colorful common names. Among these are "Locomotive cicada," "Popcorn-Whistler," and "Soupbug" in the United States and "Chichara grande" and "Coyoyo" in Argentina. The "Soupbug" appelation comes from its occasional attraction to lights during its evening flights and its consequent appearance on the dinner table. Quesada is subject to a fungus disease which attacks the terminal portions of the abdomen. It is also attacked by a "Cicada killer," a sphecid wasp. CHAPTER XXI Tibiaen Taxonomy Tibicen Latreille (1825, p. 426) Type Species Tibiaen plebeja (Scopoli) (Latreille, 1825) = Cicada plebeja Scopoli = Tettigo?iia cvni Fabricius (nee Linne) = Tettigonia fraxini Fabricius = Tettigonia obsciwa Fabricius = Cicada obscura (Fabricius) = Lyristes plebeja (Scopoli) = Cicada fraxini (Fabricius) Species There are thirty species of Tibicen in North America north of Mexico and eight additional named varieties. The species are T. auletes (Germar) T. chisosensis Davis T. aurifera (Say) T. chloromera (Walker) T. bifida (Davis) T. cultriformis (Davis) T. caniculai'is (Harris) T. davisi (Smith and Grossbeck) T. chiricah.ua Davis T. dealbaza (Davis -133- -184- T. dorsata (Say) T. latifasoiata (Davis) T. duryi Davis T. winnemanna (Davis) T. figurata (Walker) T. vesh (Haldeman) T. inauditus Davis T. vesonans (Walker) T. linnei (Smith and Grossbeck) T. vobinsoniana Davis T. longiopevoula Davis T. similavis (Smith and Grossbeck) T. lyvicen (De Geer) T. supevba (Fitch) T. montezuma (Distant) T. texanus Metcalf T. pavallela Davis T. townsendii (Uhler) T. pruinosa (Say) T. walkevi, Metcalf Metcalf (1963) lists two additional species of Tibicen with ranges north of Mexico, T. vai^legata (Fabricius) and T. ocveopteva (Townsend) . Davis (1918) tried to identify Fabricius' T. vaviegata but concluded "owing to a faulty description" it might "be one of several of our well-known species." He apparently could not locate an identified specimen, and the species still remains unidentifiable. The name has not been used for sixty years except in Metcalf s catalogue. Myers (1929) cites T. ocveop- teva. as a ncmen nudum. No subsequent description or types have established this species, and it has not been referred to since Myer's work except in Metcalf 's catalogue. I have, therefore, dropped these two names from the list. Both Metcalf (1963) and Alexander (unpublished) consider T. latifasoiata and T. winnemar.na as varieties or subspecies of T. pvuinosa; however, both Davis and Van Duzee treated them as separate species in their writings so I have listed them as such. There are three recognized varieties of T. lyvioen and one each of T. pvuinosa, T. walkevi, T. bifida, T. ohlovomeva, and T. davisi. -185- Descriptive History Confusion as to what actually constituted the genus Tibicen was intimately entangled for almost a hundred years with a similar confusion over what was intended by the original Linnean genus Cicada. In 1825, Latreille named Tibicen for plebeja Scopoli without description. Had he left well enough alone, the confusion might not have arisen, but in 1829 he named "one distinguishing character (of no value) . . . and four species (belonging to three genera)" (Van Duzee, 1914). Since plebeja was frequently used as the type for Cicada, subsequent authors felt free to use the other species named in 1829 as types for Tibicen. Some authors, notably Distant, ignored the genus altogether. Distant, in Genera Insectorum (1912), used plebeja as his type for the genus Cicada. Van Duzee (1912) quickly pointed out that Cicada as characterized by Distant no longer included any of the original Linnean species. In 1914, Van Duzee declared C. ovni the type for Cicada based on Lamarck's naming of ovni in 1801 and other evidence indicating Linnaeus intended ovni as the type for his section "Manniferae. " He returned to the original naming of Tibicen in 1825 and reiterated plebeja as the type for the genus. He further established the genus by placing our American species in Tibicen in his Check List of Hemiptera (Excepting the Aphididae, Aleurodidae and Coccidae) of America North of Mexico (1916) and his sub- sequent catalog of the same species (1917). Tibicen, as recognized by Van Duzee, included the then described species of our presently recog- nized genera Tibicen, Diceroprocta, and Covnupluva. Van Duzee did not describe Tibicen. Various short descriptions, usually relating to diag- nostic characters of local species, have appeared, but I have been unable to locate a fuller treatment of the genus. -186- Description General Body Proportions Length of body 22.0 to 41.0 mm Expanse of forewings 60.0 to 125.0 mm The above size range applies only to Tibiaen from North America north of Mexico. Both larger and smaller species have been described from other areas. The abdomen represents about one-half the body length in females but is generally slightly longer in males because of the extended male genitalia. The length of the body is at least two and one-half times the width of the mesonotum. Head Width of head, including eyes, about as broad or broader than mesonotum; eyes may extend slightly beyond the anterior margin of the pronotum; vertex of epicranium horizontal, frons nearly vertical, forming a right or sharply obtuse angle with the dorsum of the clypeus; distance between ocelli less than distance between lateral ocelli and eyes; clypeus ranges from more or less truncate, in a continuous line with the supraantennal plates, to moderately tumid; dorsum of clypeus about as long or longer than frons; length of rostrum species specific, ranging from middle coxae to beyond posterior coxae. Thorax Pronotum ampliated laterally forming definite lateral carinae, lateral edges smooth, not toothed, occasionally spinose; length of pronotum shorter than mesonotum; mesonotum obscuring central portion of -187- metanotum; opercula in males large, longitudinal, meeting or overlapping medially. Legs Anterior femora with two prominent spines beneath, sometimes with a third smaller spine distally; posterior mera triangular. Wings Forewing venation is illustrated in Figure 23. Both wings hyaline; first and second crossveins in forewings oblique, virtually parallel, and frequently infuscated; length of R, ,. between the first and second crossveins less then R, , _ between the first crossvein and the ambient 4+5 vein; medial and cubital veins arising separately from the arculus; nodus central; costal margin of the forewings with at least a few minute spines . Abdomen First abdominal segment in males containing tymbal organs, central dorsal sclerite with basically the same curvature as succeeding tergites; second dorsal segment in males produced anteriorly on each side into a complete tymbal cover; lateral bulge inconspicuous. Sexual Characteristics Ninth dorsal segment of males rounded laterally, usually produced into a central spine dorsally; uncus withdrawable, simple (Figure 23). Subgenital plate of female smoothly biiobed (Figure 23). Figure 23. Tibicen. A, dorsal view of male; B, ventral view of male abdomen; C, terminal segments of female venter; D, caudal view of male abdomen showing uncus; E, map showing the dis- tribution of the genus by state and province. Small dots are used for the smaller eastern states and provinces. Although Tibicen has not been reported from Wyoming, this state falls within the north-south range of T. dealbata, which is presumed to be there. This presumed distribution is marked by an open triangle. Arrows indicate diagnostic characters. Species illustrated is T. duryi. -189- -190- Diagnostic Characters Tibicen is most notable for its lack of diagnostic characters. Therefore, combinations of characters must be used to identify the genus. Males can be distinguished by the complete tymbal cover, broad head, opaque abdomen, simple uncus, and smooth ventral edge of the pygofer. Female identification requires the following combination of features: a) mesonotum covering central portion of metanotum, b) first and second crossveins of wings parallel, c) no infuscated markings on longitudinal veins of forewings, d) head about as broad or broader than mesonotum, e) lateral edges of pronotum smooth, not jagged or toothed, f) subgenital plate smoothly bilobed, not sinuous, g) distance between the crossveins along R less than distance between the first crossvein and the am- 4+5 bient vein. To distinguish female Tibicen from female Cornuplura, it is necessary to look under the subgenital plate for the eighth abdominal sternite. If the subgenital plate lies flush against the body and the eighth sternite can, therefore, not be seen from a caudal view, the above characters will identify Tibicen. If two "hook-like" projections emanating from the eighth sternite are visible, the specimen is either Cornuplura, Tibicen townsendii, or T. cultriformis . The basal cell of the forewing in both species of Cornuplura north of Mexico is predominantly black. In T. cultriformis it is green and in T. townsendii it is a light brown. Distribution The genus Tibicen is widely dispersed throughout the north temperate areas of the world in both the Palearctic and Nearctic biogeographic regions. There are also several species in the Neotropical region. -191- There are scattered reports of Tibiaen from all the commonly recognized biogeographlc regions except the Australian. Tibiaen reaches its greatest known diversity in the Nearctic. The number and diversity of Tibicen seems, however, to be a part a consequence of the location and conceptual outlook of the taxonomists who have worked since Van Duzee firmly estab- lished the genus in 1916. Thus, Van Duzee and Davis clarified the status of Tibicen in North America. Kato has thoroughly studied the cicada fauna of Japan during the past half century and records seven species and several named varieites in Fauna Japonica, Cicadidae (1961). I am hesitant to accept reports from the Ethiopian, Oriental, and Oceanic regions without further verification. For example, the lone Tibiaen from the Ethiopian region comes from Madagascar. While this distribu- tion is improbable, it is no less improbable than the distribution of iguanid lizards which are restricted to the Americas, Madagascar, and Fiji (Darlington, 1957). Tibiaen, which also is recorded from Fiji, is at least present currently on some Old World continental land masses. Further exploration and reworking of museum specimens may indeed reveal a truly cosmopolitan distribution for Tibiaen, or they may prove earlier records spurious. Boulard is currently working extensively on the African cicada fauna. In several recent papers on African cicadas, he has yet to record the presence of Tibiaen in the Ethiopian region of the African continental land mass (Boulard, 1972a, 1972b, 1974a, 1974b, 1975b, 1975c, 1976b). In North America north of Mexico, Tibicen is distributed from Manitoba to Nova Scotia in the north and from Florida to Arizona in the south. Tibicen is found from the east coast to Manitoba, Montana, Utah, and Arizona. Although I have seen neither specimens nor reports from -192- Wyoming, I assume Tibiaen is found in at least the eastern portion of that state since Davis (1930) records T. dealbata as extending from "Montana and North Dakota southward to New Mexico and Texas." Discussion If I were asked to select a generalized cicada from among the North American genera, it would have to be the genus Tibicen. From the broad head to the simple uncus, there is not a single feature, I have observed, that Tibiaen fails to share with at least one other genus. Diceroprocta and Covnuplura appear obviously closely related to Tibicen and the three genera form a natural grouping. Nevertheless, the more distant genera that do not retract the male genitalia, have a simple uncus. This occurrence of common features is not only found in living forms but also among fossil Cicadidae. Cooper (1941) states the oldest known fossil cicada, Davispia bearcveekensis Cooper from the Paleocene, resembles Tibicen more closely than it resembles any other modern genus. He also finds no reason why the fossil Cicada grandiosa Scudder from the Miocene should not be considered Tibicen. Both of these fossil species are from North American deposits. The fossil record seems to indicate that Tibiae? and its immediate antecedents have been in North America north of Mexico for several million years. Among living Tibicen, Davis (1930) recognizes three distinct groups in America north of Mexico. The first group he characterizes as large, usually black and green cicadas. These cicadas inhabit the eastern half of the United States and Canada. The second group averages somewhat larger than the first group and is characterized by two "pipe-shaped" marks on the mesonotum resembling the inverted Hebrew letter resh. These -193- cicadas also frequently have a row of dorsal spots on the abdomen. This group inhabits the central portion of the United States with one, Tibiaen auitvi formis , occurring in Arizona. Both of these groups have gently tapering abdomens. The third group contains the smallest species of American Tibiaen north of Mexico. They inhabit the southwestern United States and are characterized by having the sides of the abdomen con- spicuously parallel to each other. While the first two groups may be distinct in color and patterning, I see no basic morphological dif- ferences between them. The difference in shape between the third group and the other two is quite obvious. Davis states the third group most closely resembles the type species, Tibiaen plebeja. The first two groups seem to resemble more closely the species of Tihiaen illustrated by Kato (1961) in Fauna Japonica. The majority of Tibiaen species are arboreal, but, as might be ex- pected in a genus this large, different species have adapted to a wide variety of plant types. Beamer (1928) records panic grass, Paniaum virgatum, as the favored host of T. aurifera, and dead yucca fruiting stalks as the predominant oviposition site of T. bifida. Tibiaen also vary in the temperature and moisture requirements of their habitat, ranging from the "swampy woods" dwelling T. ohiovomeva in Michigan (Moore, 1966) to the xerophilous T. ahiriaahua and T. duryi of Arizona. Tibiaen are frequently solitary species, and males, at least, appear to be somewhat sedentary. I have observed a male T. pimniosa singing from the same hackberry tree throughout his adult life of several weeks in central Illinois. Tibiaen occasionally occur in large broods, and several individuals may be heard singing from the same tree or clump of trees. This clumping appears to be the result of an accident of -194- birth rather than the congregating behavior seen in Magicicada. The song of one individual frequently evokes singing by nearby males, but the songs are not necessarily synchronous. In T. figurata from Florida, one male will sing, then another, and when the second individual stops, the first male and sometimes a third will take up the song. Moore and Kausch (1975) record the mating clicks in Magicicada septendecim in the film, Seventeen-Year Cicadas {Magicicada septendecim). I have observed similar mating sounds in T. duryi. Birds are probably the most common predators of Tibicen. Attacks recorded by other insects include the asilid fly Dasyllis gvossa (Fabr.) on Tibicen chloromera, the sarcophagid Sarcophaga helicis (Town.) on Tibicen linnei, and a braconid egg parasite of Tibicen walkeri (Myers, 1929). Davis (1924, 1925) records Vespa cvdbvo (Linn.) eating T, lyvicen and T. chloromera, while the cicada killer wasp, Sphecius speciosus Dru. collects several species of Tibicen as food for its young. In addition, I have observed several large dipteran puparia associated with a dead T. figurata male in Florida. Members of the genus Tibicen are known throughout the eastern United States and into Canada as the "dog-day cicadas" because of their presence during the hot days of mid and late summer. Tibicen auletes is the largest cicada in North America north of Mexico. CHAPTER XXII Tibioinoides Taxonomy Tibioinoides Distant (1914, p. 166) Type Species Tibioinoides oicpreosparsa (Uhler) (Distant, 1914) = Tibioen oupreosparsa Uhler = Tibioina oupreosparsa (Uhler) Species There are two species of Tibioinoides in North America north of Mexico. The species are T. oupreosparsa (Uhler) T. mercedita (Davis) A third species T. minuta (Davis) is considered synonomous with T. meroedita by Simons (1954). Tibioinoides hesperia belongs in the genus Okanagana (Davis, 1919a; M.S. Heath, 1976). Descriptive History All of Distant 's (1914) characters are well illustrated by the type species; however, not all occur in T. meroedita. The following description -195- -196- is inclusive of the genus as currently recognized. Both Davis (1919a) and Van Duzee (1915) include the species of Tibioinoi.de s in their keys. Description General Body Proportions Length of body 16.0 to 20.5 mm Expanse of forewings 33.0 to 44.5 mm The abdomen longer than space between apex of head and base of cruciform elevation (Distant, 1914). Head Width of head, including eyes, narrower than the mesonotum; eyes in a line with the anterior angles of the pronotum; vertex of epicranium centrally sulcate and horizontal; frons steeply slanted, forming an obtuse angle with the dorsum of the clypeus; distance between lateral ocelli slightly greater than distance between lateral ocelli and eyes; clypeus steeply rounded, extending well beyond the supraantennal plates; dorsum of clypeus longer than frons; "rostrum reaching the intermediate coxae" (Distant, 1914). Thorax Pronotum ampliated laterally forming definite lateral carinae, lateral edges smooth, sinuate, posterior angles dilated; pronotum gradually narrowing anterioraly; length of pronotum shorter than meso- notum; mesonotum striated where base of forewing folds against the body; posterior margin of metanotum completely visible behind mesonotum; -197- opercula small, transverse, rounded, widely separated, not extending beyond the base of the abdomen. Legs Anterior femora armed with two prominent spines; posterior mera broadly triangular. Wings Forewing venation is illustrated in Figure 24. Wings hyaline to semiopaque, the basal half of the forewings sometimes heavily infuscated especially behind a rudimentary crossvein marking the transverse fold of the forewing, that may be well developed in some specimens of this genus. First and second crossveins in forewing slightly oblique and usually parallel; marginal cells of forewings short, about one-half the length of the ulnar row, especially the ratio of M to U„ ; "basal cell about twice as long as broad" (Distant, 1914); medial and cubital veins arising separately from the arculus; nodus central; costal margin not notably spinose; wings may be setose, especially in opaque areas and around veins. Abdomen First abdominal segment in males containing tymbal organs, posterior margin of central dorsal sclerite broadly curved anteriorly, margin occasionally sinuous (Figure 24); anterior margin of second dorsal sclerite ending abruptly, may or may not turn outward to form a ribbon- like structure posterior to the tymbals; lateral bulge well developed; tymbal organs exposed. Figure 24. Tibicinoides . A, dorsal view of male; B, ventral view of male abdomen; C, lateral view of terminal segments of the male and dorsal view of the uncus (after Simons, 1954); D, map showing the distribution of the genus by state. Arrows indicate diagnostic characters. Species illustrated is T. aupveosvarsa. -199- D -200- Sexual Characteristics Ninth dorsal segment of males rounded laterally, caudal margin with an anterior curve dorsally; uncus stationary, not retractable, simple (Figure 24); hypandrium elongated. Subgenital plate of female with a deep, single U or V shaped notch (Davis, 1915). Diagnostic Characters The short marginal cells on the forewing will identify Tibioinoides from other cicada genera found in North America north of Mexico. Distribution North of Mexico, the genus Tibioinoides is reported only from California. Simons (1954) states, "The genus Tibioinoides is found primarily in the western part of the state (California) , extending as far north as Lake County and reaching southward into Lower California." Discussion Tibioinoides, as currently recognized, consists of two, small okanaganoid species. The genus appears to be the nucleus of a group in transition with the type species, Tibioinoides cupreosparsa, the most divergent from Okanagana. The semiopaque (or heavily infuscated) wings sometimes accompanied by a well developed rudimentary vein running from the base of the first ulnar area to the base of the "lower apical area," and included by Distant (1914) in his original description of Tibioinoides, appears to be a polymorphism found in both Tibioinoides and some species of Okanagana. Okanagana hesperia exhibits distinct, -201- independent polymorphism in body and wing coloration with intermediate forms occurring in both. A transverse fold, or rudimentary vein, crossing the forewings at the node may or may not be developed. The dark winged forms have been frequently placed in the genus Tibioinoides, whereas the clear winged form was described originally as a variety of Okanagana stviatipes. The species conforms in all other features with Okanagana and has been placed there by Davis (1919a) and M.S. Heath (1976). Since wing patterning can no longer be considered diagnostic of the genus, we must look for structural features. The clypeus is much more rounded in Tibioinoides than it is in O'kanagana. In that feature it more closely resembles the other two okanaganoid genera, Okanagodes and Clidophleps. The anterior margin of the second abdominal tergite in T. mevoedita resembles the same structure in Okanagana and Clidophleps , while the tergite in T, oupreosparsa resembles that of Okanagodes. The only unique feature of the genus is the short marginal cells in the wing. Tibicinoides is thus closely related to Okanagana, Clidophleps, and Okanagodes. Tibioinoides are active as adults from late April to late June. Both species are found in grass (Van Duzee, 1914; Simons, 1954). Davis (1935) records an interesting behavioral note en T. meroediva. This species feigns death when disturbed. Both males and females fold their legs and drop to the ground. They remain comatose even when handled and will wait several minutes before resuming activity. Tibioinoides possess a striated surface where the fcrewing folds against the mesonotum. A similar structure is found in Clidophleps , Okanagodes, and some species of Okanagana. This is apparently the stridulitrum (Ashlock and Lattin, 1963) of a secondary sound producing mechanism used for communication by both males and females. CHAPTER XXIII DISCUSSION AND CONCLUSIONS Origins and Dispersal The entire cicada fauna of North America north of Mexico is endemic. At least two genera appear to have their origins in the Neotropical biogeographic region. Quesada barely slips over the southern border of the United States into southern Texas, yet its range extends southward into Argentina. Paaarina presently is represented by one species in the American southwest, and diversification occurs only in the Neotropical region. A third genus, Beamevia, may have its closest relatives in the neo tropics. The type species B. venosa was originally classified as a member cf a neotropical genus. Although Beamevia is known to occur only north of Mexico, Metcalf (1963), who relies heavily on geographical centers of origin for all taxcnomic levels, places Beamevia in the same tribe with Paaarina. Neociaada has its closest morphological affinity with the genus Cicada, a widely distributed Palearctic genus. A Cicada-like ancestor probably crossed the Bering land bridge at some point in the geologic past. The most widely distributed of all cicada genera, Ciaadstta, is represented in the Nearctic region by only four species. It is not found in the Neotropical region. Cicadetva' s invasion of North America must have occurred in a manner similar to that of 7ieca-icada. 102- -203- Magicicada is a North American phenomenon. There is nothing else quite like it. Several anatomical features suggest, that despite its remarkable synchronous periodicity, Magicicada is a somewhat primitive cicada. It may well be that remnant of an ancient cicada fauna once in- habiting the North American continent. There seems to be no justifica- tion for the traditional lumping of Magi.ci.cada in the same tribe, Tibicinini, with Okanagana and its derivatives. Myers (1929) considers Tibicinini a catchall of unrelated genera, and I agree that a thorough reworking of the material within this tribe is called for. The above six genera, with the possible exception of a loose rela- tionship between Beameria and Pacarina, stand as solitary generic representatives in the region of North America north of Mexico. The current distribution of both Neocicada and Cicadetta suggest that, like the other North American cicadas, the presence of both antidates Pleistocene glaciation in North America. Several writers have noted the effects of glaciation on the distribution of broods of Magicicada. The remaining ten genera can be divided into two primary groups, those derived from the genus Tibicen or its immediate predecessor and those derived from Okanagana and/or its predecessor. This latter group is comprised of two subgroups, one containing Platypedia and Neoplatypedia and the other comprised of the four okanaganoid genera. There are two basic shapes found in the genus Tibicen. One is the parallel sided habitus characteristic of the type species Tibicen plebeg'a from Europe. The other is a gradually tapering form characteristic of the Japanese Tibicen as illustrated by Kato (1961). Both forms are found in North America north of Mexico. Parallel sided species are found predominantly in the southwestern United States and on the eastern -204- slopes of the Rocky Mountains. Their eastern border appears to be the Great Plains. The tapering species are found predominantly in the eastern United States and Canada. Although some species appear to have followed river courses into the eastern fringe of the parallel sided group, and one species, Tibicen cultriformis , is found in Arizona, their western dispersal also seems limited by the Great Plains. I believe that there were two invasions of Tibicen or Tibicen-like ancestors into North America, one representing each of the two basic forms. The parallel sided group appears to be the earlier invader because Neotropical Tibicen have the parallel sided appearance, and this group has diversified into three additional genera. The tapering habitus is more limited in distribution and has not diversified into additional genera. Parallel sided Tibicen apparently spread southward along the eastern slopes of the Rockies into Mexico and eventually into South America. Somewhere in central Mexico this group radiated into Diceroprocta , Comuplura, and Cacama. These three genera then spread back northward. Diceroprocta spread across the southern United States from the Colorado River valley to the eastern seaboard and is now found as far north as Michigan, Wisconsin, and Virginia. Comuplura has reached southern Arizona, and Cacama inhabits the southwestern United States in- cluding southern California. Tibicen and its three related genera are still found in Mexico. The gently tapering Tibicen form entered North America later. It did not disperse southward along the eastern slopes of the rockies probably because the Tibicen niches already were occupied. Instead, it dispersed eastward along a northerly route until it reached territory unoccupied by other Tibicen east of the Great Plains. There ensued a -205- radiation of species southward throughout the eastern United States. This group has not spawned any new genera. The second major group of genera in North America north of Mexico is that derived from or sharing a common ancestor with Okanagana. This group apparently has a loose relationship with the Palearctic genera Tibiaina and SubpsaXtria and the Neotropical genera making up the sub- family Tettigadinae with which they share an accessory stridulatory surface near the "shoulder" of the mesonotum. Tibiaina and Okanagana. have other characters in common. I propose that a common ancestor of these two genera entered North America across the Bering land bridge, and that this ancestor developed into an Okanagana somewhere in northwestern Canada. From there it spread eastward to the Atlantic. There is a small radiation of species of Okanagana in the eastern United States and Canada. This radiation was probably restricted by the presence of other cicada genera already occupying the cicada niche in eastern North America. Okanagana. also spread southward west of the Rocky Mountains. Here it found a territory unclaimed by other cicadas. It radiated into a variety of species and genera particularly in the diversified habitats afforded in California. It is probably fortuitous that the distribution of the type species of Okanagana, 0. vimosa, follows both the eastward and southward distribution today. All six of the genera in this group, Okanagana, CXidophXeps , Tibicinoides , Ckanagodes , PXatypedia, and Neoplatypedia, reach their greatest diversity of species in California. Four species comprise one subgroup. Okanagana has remained boreal in the western United States extending its range southward along the mountain ranges. Tibiainoides is restricted to western California and Baja California. CXidophleps and •206- Okanagodes have adapted to more arid habitats. Okanagodes has spread across the southwestern deserts to Texas, while Clidophleps has remained in southern California and Baja California with the exception of one species found in Arizona. The other subgroup consists of Platypedia and Neoplatypedia. It is probably an earlier diversification than that of the above genera. Al- though these two genera have deviated strikingly from other North American cicadas, the deviations are all related directly to the loss of the traditional sound producing tymbal organ and the development of a dif- ferent method of sound communication. The nonretractable, simple uncus definitely relates them to the okanaganoid group. Platypedia probably had its origins in an okanaganoid-like ancestor that lacked a mesonotal stridulatory surface. Neoplatypedia derived from Platypedia. Both have a basin and range distribution, with Platypedia reaching the northern plains. It appears to me that the above six genera, and possibly Tibioina, and Subpsaltria, should form the basis of a new tribe. The new tribe would consist of at least two subtribes. Traditionally Tibioina and the four okanaganoid genera have been placed in the Tibicinini with Platypedia and Neoplatypedia placed in their own subfamily or family because of the lack of a functional tymbal organ. I believe evolutionary relationships would be more clearly shown by a new tribal designation. I propose the name Okanaganini for the tribe with Platypedaria for one subtribe con- taining Platypedia and Neoplatypedia and Okanaganaria as the other sub- tribe encompassing the other genera. It is difficult to establish a time line for these various invasions and dispersals. Cicadas disperse slowly. Although cicadas are capable -207- of strong flight, females usually oviposit in the general region where they mate. They do not fly away in search of a new, suitable location. Dybas and Lloyd (1962) did observe M. aassini and M. septendeaim colonizing a grove of young ash across a clearing from a more mature habitat where the nymphs emerged. The fossil record is not particularly helpful either. The oldest fossil, Davispia beavcreekensis from Montana, is a wing that dates from the Paleocene (Cooper, 1941). This wing resembles the wing of Tibicen. Cooper also considers Cicada gvandiosa from Miocene beds in Colorado a Tibioen. Lithooicada per*ita and Platypedia prirrrigenia are from the same Miocene beds. Cooper feels Lithooiaada pevita has an expanded radial cell approaching Platypedia. It is probably reasonable to assume that the current genera were present somewhere in North America before the Pleistocene. Ecology and Distribution Very little is known of the ecology of North American cicadas other than the genus Magieiaada, and man has altered their natural habitat con- siderably. Nevertheless, a few generalizations can be proposed regarding the division of the habitat on an ecological basis. Six genera inhabit the eastern United States and Canada. Magieiaada is associated with the eastern deciduous forest. It thrives in areas with deep, fertile forest soils. Neooiaada, on the other hand, is associated with oaks growing in sandy soil. Both are arboreal. Ciaadeita, with much the same state by state distribution as Neocieada, inhabits grasses and weeds. The boreal origins of Okanagana have already been mentioned. In the eastern United States with the exception of one species, Okanagana is restricted to more northerly states. Ambient temperature and/or temperature fluctuations may -208- have an effect on the distribution of Okanagana. Tibicen overlaps the distribution of the other genera and is found throughout the eastern United States and southeastern Canada. Most Tibicen are arboreal. The large number of species suggests that each species is associated with a particular habitat or more narrowly defined niche. Tibicen are more wary of predators than Ciaadetta or Magicicada. They are frequently solitary. Some species may escape predator pressure by being distributed sparsely among large numbers of other cicadas. I would not expect to find a large population of Tibicen in the same location the year following an emergence of Magicicada. The final eastern genus, Diceroprocta, spreads across the southern United States from the Colorado River basin to the Atlantic coast. It is found in the arid southwest and along the Gulf and eastern coastlines. The "salt-marsh" cicada, Diceroprocta veridi fascia, belongs to this genus. It is not clear what limits the distribution of Diceroprocta; however, many species, even in the southwest, have obviously expanded their ranges by following stream or river courses. Food toler- ances may be important in their distribution. Tibicen, Diceroprocta, and Okanagana are also found in the West, although Tibicen does not reach the far western states. Okanagana have expanded their western distribution by following mountain chains. Isolated populations of Okanagana found on the disjunct mountains of the Southwest attest to their geologic history. Cornuplura is associated with oaks in southern Arizona while the distribution of Cacama is closely tied to the distribution of Opuntia. Quesada is an arboreal genus throughout its range. Our knowledge of Pacarina is scant, but Juniper may be a factor in its distribution. Beameria inhabits dry, rocky grasslands. Yucca may also influence Beameria* s distribution. Another -209- grass dwelling genus is Tibiainoides , which inhabits the grassy slopes found in western California. Okanagodes live in true desert conditions, while Clidophleps prefers chaparral. The ecology of Platypedia and Neoplatypedia is not well known. Some species definitely have adapted to the high northern deserts where they inhabit sagebrush, but others live in streamside vegetation, and still others may inhabit the scrubby elements of a forest understory. Three major geographic features appear to be major deterrents to cicada dispersal in North America north of Mexico. These are the Rocky Mountains, the Great Plains, and the southwestern deserts. Another element of cicada ecology is the relationship of cicadas to other organisms in their environment. During large emergences, cicadas may be a primary food source of birds and rodents. They are attacked by predaceous insects and spiders. Some of the insects known to feed on cicadas are mantids, dragonflies, and robberflies. Cicada killer wasps use them to stock their nests as food for developing larvae. Chalcids have been reported as egg parasites, and some Diptera, apparently summoned by the song of the males, parasitize adults. At least three genera are subject to fungus diseases, Magiaicada, Okanagana, and Quesada. In the past man has utilized cicadas as a source of food. I am told the flavor resembles a nut. Evolution of Higher Taxa Schaefer (1976) points out that higher taxa, including genera, are the result of real biological phenomena, exemplified by the occupation of a new niche, such as a new behavior, a new locality, or a new food resource. Three examples stand out among the cicadas found north of -210- Mexico. One is the invasion of the western United States, particularly California, by an Okanagana prototype. The release from competition in a favorable climatic habitat with a wide variety of suitable cicada niches resulted in a burst of species and genera which should be regarded as a supergeneric or tribal taxon. In this case the new niche was an unoccupied locale. Undoubtedly the early radiation was specific. As the favorable niches became filled with species of Okanagana, those on the fringes adapted to utilize the other unoccupied habitats, such as desert and grass, and new genera were formed. Somewhere in the radiation of the Okanagana ancestor, a new means of communication developed. This resulted eventually in a second super- generic group represented by Platypedia and Neoplatypedia. This was the occupation of a new behavioral niche. Cacama is an example of a group that has arisen because of its ability to utilize a new food resource. The bumble-bee mimicry of body shape and color along with a hovering takeoff and landing pattern may have developed first as examples of protective coloration and behavior. These changes enabled Cacama to exploit Opuntia as a food resource with the subsequent radiation of species. This is an example of both a new behavioral and a new food niche providing the impetus for the evolution of a new genus. Evolution and Morphology It is not possible on the basis of the sixteen North American genera found north of Mexico to construct a complete phylogeny since many of these genera have their "roots" in other geographical regions. It is possible, however, to indicate some characteristics which appear to be -211- ancestral and some that appear to be derived on the basis of this limited sample. Structures Associated with the Tymbal Organs Since the discovery of tymbals and tymbal muscles in other auchenor- rynchous Homoptera by Ossiannilsson (1949), it has become clear that this character, long associated only with cicadas, is ancestral. In the Cicadelloidea and Fulgoroidea, this structure may be associated with both sexes, or it may be better developed in one or the other sex. Pringle (1954) attributes the loud call of the male cicada to the develop- ment of a resonating chamber in the form of a largely hollow, air-filled abdomen. The origins of this chamber and associated modifications of internal abdominal structure in nymphal cicadas is not completely re- solved. Pringle feels it is part of the tracheal system. Female cicadas were unable to develop a resonating chamber of similar magnitude because the abdomen is largely occupied by the developing ovaries. Therefore, the loss of the tymbal organ and associated muscles in female cicadas is a derived state. The loss of a functional tymbal and associated muscles in males of two North American genera, Platypedia and Neoplatypedia , is derived. A similar loss has been noted by Boulard (1973a, 1975a) for the African genera Ydiella and Lamotialna, and by Chen (1943) for the Chinese genus Sinosensa. The "chitinous V" is an infolding of the exoskeleton forming the basal attachment of the tymbal muscles. The tymbal muscles fold around the arms of the "V." A second strut arises on each side near the base of the chitinous V. In the genus Platypleura these struts or ridges fuse medially providing a strong additional surface for the attachment of the -212- muscles (Pringle, 1957). In Tibiaen these ridges almost meet (Myers, 1928). However, in Magiaicada the chitinous V is merely "buckled in- ward" (Pringle, 1957). Pringle considers the condition as found in Magiaicada primitive, the condition in Platypleura the most advanced status, and the structure of Tibiaen somewhere in between. If the shape of the chitinous V affects the shape of the tymbal muscles as seen in the radiographs (Figure 8) , then the modified hexagon seen in Magiaicada can be considered ancestral or primitive for this character. Externally the tymbal organ is protected on the dorsal side by a protrusion of the second abdominal tergite in some genera. Other genera completely lack a dorsal tymbal cover, while in some the tymbal organ is only partially protected. These tymbal covers vary in shape and size. They apparently have arisen several times. One group of cicadas has tymbal covers emanating from the metanotum (Boulard, 1976a). It appears, therefore, that a lack of tymbal covers is the ancestral state and the presence of tymbal covers is derived. Similarly shaped covers probably indicate a phylogenetic relationship, as in the case of Cacama, Diceroprocta, Tibiaen, and Covnupluva, or Neoaiaada and Cicada. The opercula protect the tymbal organs ventrally. While it is not possible to ascertain a primitive or derived state for the opercula from the limited sample represented by the North American genera, two charac- teristics appear to be important. The opercula may be widely separated or they may meet centrally. They may be short, curving inward, or they may extend longitudinally over the abdomen. Similar opercular develop- ment may indicate an evolutionary relationship. Thus, the four okanaganoid genera have short, transverse, rounded, widely separated opercula. Tibiaen and its derived genera have longitudinal, overlapping -213- opercula. Dicevopvoeta exhibit both rounded and triangular opercula. The triangular shape may be considered derived. Opercular development does not correspond necessarily with tympanal covering development. Magicicada has well developed opercula but no tymbal covers. A large medial extension of the metathorax is found in Beameria between the two opercula. This projection is assumed to be a derived character. Distant, Metcalf, and others have used tymbal covers, or the lack of them, for major divisions of cicadas. Cicadas can indeed be divided into the two major groups suggested by Metcalf (1963) but not on the basis of tymbal covers. The line between partial tymbal covers and no tymbal covers becomes ambiguous in genera such as Quesada and Beamevxa. A more reliable character is the visibility of the metanotum behind the mesonotum, or whether it is obscured centrally by an overlapping mesonotum. This character is more valuable because it can be seen in both male and female specimens. All the genera considered here with tymbal covers have the metanotum obscured centrally. This is, therefore, considered the derived state, and the exposed metanotum is considered the ancestral state. Male Sexual Characteristics The male uncus has been used extensively as a taxonomic character in North American Cicadidae. There are two primary characteristics. One is the retraction of the uncus with the pygofer so that in a non- copulatory male the uncus lies in a ventral, unexposed position. This is the general cicada condition and, therefore, is considered ancestral. In the other character state the uncus is elongated, remains exposed, and forms a dorsal shield for the phallus. This condition or structural dis- arrangement is found in six North American genera, Okanagana, Okanagodes, Clidophleps , Tibicinoides, Platypedia, and Neoplatypedia and is considered derived. The second taxonomic characteristic of the uncus is its shape. The shape is species specific, but a generalized pattern is character- istic of a genus. The generalizes shape of the male unci in the genera north of Mexico form a "phenocline" (as defined by Ross, 1974) with Magiaioada at one end and Cornuplura at the other. In Magi cicada the uncus forms two distinct lateral lobes. These lobes are close together but remain distinct in Pacarina and Cicadetta. In Diceroprocta, Beameria, and Quesada the two sclerites meet at the base. In the re- maining genera they are fused into a single piece. This piece may be notched posteriorly. In Cornuplura the notch has expanded to form two separate prongs, but the uncus remains fused at the base. Although the majority of North American genera north of Mexico have a simple, fused uncus, because six of these genera derived from a common ancestor, this is not considered the primitive condition. The ancestral state is more likely closer to Magicicada or Pacarina with the other states being derived. The simple, exposed uncus was likely derived from a simple retractable uncus. Accessory Sound Producing Mechanisms An accessory stridulatory surface on the anterior, lateral portions of the mesonotum is found in four genera of cicadas occurring in North America north of Mexico. Within this region the mechanism reaches its greatest development in the genus Clidophleps. This feature was initially described by Jacobi (1907) in the Tettigadinae and has subsequently been used by taxonomists as a key feature at all taxonomic levels from -215- species to family. It is the only key feature used by Kato (1961) to identify the family Tettigadidae. Boulard (1976a) has subsequently discovered the presence of a "tettigadien" type stridulitrum (Ashlock and Lattin, 1963) in a variety of genera from very diverse geographical areas. He specifically identifies Tettigades, Calliopsida, Babvas, and Chonosia. Presumably other genera making up the Neotropical subfamily Tettigadinae also exhibit this character. Zarmara is another Neotropical genus exhibiting mesonotal striations. Among the Palearctic and Nearctic genera mentioned by Boulard (1976a) are Tibiaina^ Subpsaltria, and Clidophleps . Chen (1943) used these mesonotal striations as the principal distinctive feature of the genus Subpsaltvia from northwest China. I have verified the presence of this striated surface in Tibicina haematodes , the type species of the genus Tibiai-na. It resembles the degree of development in several species of Okanagana. Okanagana, Okanagodes , and Tibioinoides may now be added to the list of Nearctic genera possessing a mesonotal stridulatory surface. These three genera obviously are related closely to Clidophleps. The discovery of several genera containing mesonotal striations should help elucidate evolution- ary relationships. The discovery, however, reduces the value of the present usage of mesonotal striations as a discriminating taxonomic character for some current groups. Wing fluttering when two cicadas approach each other has been observed for a long time. This was thought to be a purely visual cue, but the rustling also produces a sound. This sound is distinctly audible at night in a forest filled with Magiaiaada (J.E. Heath, 1978, personal communication) or in a darkened room with caged cicadas. In many cicadas a ridge is formed where the forewing rests against the mesonotum. The -216- sclerotized anal margin of the forewing passing over this ridge could produce a sound. It is easy to see how striations could amplify and specialize this signal. The ridge, itself, is often rough and irregular. The advantage of an accessory sound mechanism is the two way communica- tion between males and females. It is unlikely that such a mechanism would develop independently again and again. It is assumed, therefore, that those genera with similarly positioned striations are somehow loosely related. The accessory stridulatory mechanism is considered a derived character. The wing tapping of Platypedia and Neovlatypedia probably also developed as an accessory sound producing mechanism. In this case it was such a successful communication device that the tymbal organ was lost. A similar accessory wing tapping is performed by New Zealand cicadas of the genus Amphivsalta (Dugdale and Fleming, 1969). There appears to be no relation between this genus and the two wing tapping genera in North America. Wing tapping is also a derived character. 3oulard (1973b, 1976a) has found other stridulatory surfaces on cicadas. I predict additional methods of sound communication in cicadas will be discovered as investigators become more aware of this phenomenon. Wings An analysis of wing venation and structure on a world-wide basis is needed to ascertain ancestral and derived characters. The movement of the nodus from a more or less central position to the edge of the distal third of the wing in Platyped'la and Neoplatypedia. is definitely derived as is the expanded radial cell in these two genera and in some Clidophleps . -217- Eight marginal cells in the forewings is an ancestral trait; the seven in Neoplatypedia are a derived character. Summary Sixteen endemic genera of cicadas are found in North America north of Mexico. Each of these genera is redescribed in a consistent format, thereby facilitating comparisons of common characters. Keys to both males and females are presented, and the known biology of each genus is summarized. The use of soft x-rays to reveal internal characters is a new technique in insect taxonomy. Reasons for maintaining the family Cicadidae as a single taxonomic unit encompassing all cicadas are given. Five of the genera, Quesada, Paoarina, Caaama, Diceroproata, and Cornuplura have entered the geographical area north of Mexico from the south. Two genera, Tibiaen and Cioadetta, are cosmopolitan in distribu- tion, apparently entering North America across a Bering land bridge. The remaining genera have evolved in place. Six of these, Oka.wn.gana, Okanagodes, Clidophleps, Tibioinoides , Platypedia, and Neoplatypedia, appear to have shared a common ancestor. A new tribe, Okanaganini , is proposed for these genera. This tribe has two sub tribes Okanaganaria and Platypedaria. The following revisions are recognized: Okanagana rubrocaudata, a former variety of 0. bella is raised to species rank; Okanagana rotundifvons is transferred to the genus Clidophleps; Tibioinoides hespsria is moved back to Okanagana; Cicada chisos is placed in the genus Neoaiaada. Two species of Tibicsn, T. vaviegata and T. ocrecvtera, are removed from the list of North American cicadas. -218- Current distributions are related in this paper to origins, dispersal patterns, habitat, and past geologic history. Two major radiations of genera, one allied to Tibioen and the other to Okanagana, have occurred on the North American continent. The evolution of new genera can result from the exploitation of new niches. Three examples are given for North American genera. The evolu- tionary position of each of several primary characters is discussed. Cicadas are large, loud, obvious insects found in practically all habitats in North America. It is surprising that only the genus Magioioada has been well studied. Very little is known about the other genera found in the Nearctic region north of Mexico. It is hoped that this taxonomic work will lay the foundation for further studies on the biology of North American Cicadidae. LITERATURE CITED Alexander, Richard D. unpublished. Key to species of cicadas occurring in the United States east of the Mississippi River, 3rd revision. 6 pp. Alexander, Richard D. and Thomas E. Moore 1962. The evolutionary relationships of 17-year and 13-year cicadas, and three new species (Homoptera, Cicadidae, Magieicada) . Misc. Publ. Mus. Zool., Univ. Michigan, 121:1-59. Alexander, Richard D. , Ann E. Pace, and Daniel Otte 1972. The singing insects of Michigan. Great Lakes Ent. 5(2):33-69. Amyot, Charles Jean Baptiste 1847. Rhynchotes. Ordre deuxieme. Homopteres. Homoptera. Latr. Entomologie Francaise. 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BIOGRAPHICAL SKETCH Maxine Shoemaker Heath, born December 11, 1935, Los Angeles, California. Educated in Los Angeles at Hollywood High School, Los Angeles City College, Los Angeles State College, University of California, Los Angeles; and in Gainesville, Florida, at the University of Florida. B.A., 1958, U.C.L.A.; M.L.S., 1962, U.C.L.A.; M.S., 1976, University of Florida; advanced certification in biomedical librarianship , Medical Library Association. Member of the following honorary societies; California Scholarship Federation, Beta Phi Mu, Phi Kappa Phi. Vale- dictorian high school graduating class. Listed in Who's Who in Library Science, 1966. Professional experience: assistant Latin American Bibliographer, U.C.L.A.; cataloger, University of Illinois; instructor in Library Science and Physiology, University of Illinois; research assistant in Physiology, University of Illinois; associate in Zoology, University of Florida; Graduate assistant in Entomology, University of Florida. Extensive volunteer work with Girl Scouts of America, P.T.A. board, parks and recreation, public schools. Married, 1955, to James Edward Heath. Three daughters, Cynthia, Pamela, and Jessica. -231- I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Reece I. Sailer, Chairman Graduate Research Professor of Entomology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Harvey L. Cromroy, Co-chairman Professor of Entomology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Lewis Berner Professor of Zoology and Entomology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. ,-S £?& ic^ffii-*<^ Ellis L. Matheny Assistant Professor of Entomology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Frederick A. King Professor of Neuroscience This dissertation was submitted to the Graduate Faculty of the College of Agriculture and to the Graduate Council, and was accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy. August 1978 /?/& /i<2^ U-L>^ Dean, College of AgricuirEur Dean, Graduate School UNIVERSITY OF FLORIDA 3 1262 08553 2769