TB 1575/11/78 "^A SYSTEMATIC ANALYSIS OF THE PINE PITCH MIDGES, CECIDOMYIA SPP. (DÍPTERA: CECIDOMYIIDAE) m á^l) DEPARTMENT OF BULLETIN SCIENCE AND ^^ AGRICULTURE NUMBER 1575 EDUCATION ADMINISTRATION On Januar\' 24, 1978, four USDA agencies—Agricultural Research Service (ARS), Cooperative State Research Service (CSRSj, Extension Service (ES), and the National Agricultural Librarj^ (NAL)—merged to become a new organization, the Science and Education Administration (SEA). U.S. De- partment of Agriculture. This publication was prepared by the Science and Education Administra- tion's Federal Research staff, which was formerly the Agricultural Re- search Service. ACKNOWLEDGMENTS I am grateful for the aid of all those who collected and loaned material used in this study. Among them are A. T. Drooz, Forest Service, U.S. Department of Agri- culture, Research Triangle, N.C.; B. H. Ebel, Forest Service, U.S. Department of Agriculture, Athens, Ga.; R. T. Franklin, University of Georgia, Athens; J. F. Law- rence, Museum of Comparative Zoology, Cambridge, Mass.; J. F. McAlpine and J. R. Vockeroth, Biosystematics Research Institute, Agricuhure Canada, Ottawa; J. R. McGraw, North CaroUna State University, Raleigh; E. P. Markel, Forest Ser- vice, U.S. Department of Agriculture, Olustee, Fla.; K. Valley and A. G. Wheeler, Pennsylvania Department of Agriculture, Harrisburg; J. Wilcox, New York State Museum, Albany; and R. C. Wilkinson, University of Florida, Gainesville. I thank also the staff of Cedarville State Forest, Prince Georges County, Md., for allowing and helping me to collect in the forest. My colleagues in the Systematic Entomology Laboratory, Science and Education Administration, P. M. Marsh and G. Gordh kindly identified the hymenopterous parasites reared from Cecidomyia spp. CONTENTS Page Abstract 1 Introduction 1 Genus Cecidomyia Meigen 2 The Nearctic species 3 Keys to Nearctic species 4 Descriptions of Nearctic species 4 The Palearctic species 8 Literature cited 9 Washington, D.C. Issued November 1978 A SYSTEMATIC ANALYSIS OF THE PINE PITCH MIDGES, CECIDOMYIA SPP. (DÍPTERA: CECIDOMYIIDAE) By Raymond J. Gagne', research entomologist^ ABSTRACT The genus Cecidomyia contains 11 species, 8 from by use of a cladogram, and the North America spe- North America and 3 from Eurasia. Most are only cies are keyed, described, and their pertinent tax- broadly host specific and occur on many species of onomic characters illustrated. New species described pines in North America and also spruce and fir in are C. brevispatula, C. fortunactus, C. reburrata, and Europe. The larvae feed on pitch and can cause C tortilis. extensive primary damage. The species are analyzed INTRODUCTION The genus Cecidomyia contains the "pine pitch dleform, and the hind spiracles are at the extreme midges," whose larvae feed on the resin of conifers, end of the body. They are the only cecidomyiid mainly pines. Eleven species are known—eight from larvae found submerged in conifer resin. North America and Cuba, two from Europe, and This is the first complete taxonomic revision of one or possibly two from the Himalayan region. Cecidomyia, although Barnes {1951) reviewed the They are primary feeders and cause extensive literature to about 1950, and Vockeroth {I960) in his damage to pines, especially in North America. The study of the species on jack pine {Pinus banksiana larvae form pits or resinous nodules in twigs, Lamb.) reviewed much of the previous taxonomic branches, and cones, where they live completely sub- literature. Vockeroth implied a narrow host specif- merged in the accumulated resin except for their pro- icity to Cecidomyia species by treating his three spe- truding hind spiracles. cies from jack pine as distinct from those previously The genus belongs to the supertribe Cecidomyiidi. described from Pinus radiata D. Don., P. rigida The adult flies may be separated from those of other Mill., and P. virginiana Mill. To the contrary, most genera by the following combination of characters: of the Nearctic species that occur on hard pines {Pin- The tarsal claws are shorter than the empodia, us, subgenus Diploxylon) have a wide host range. I untoothed, and bent beyond midlength; the basi- found six species of Cecidomyia in a small grove of meres are stout and unlobed basally, and the male P. virginiana in Montgomery County, Md. Three of tergum and sternum X are of approximately equal them occur from coast to coast on several species of length; the ovipositor is protrusible although not pine. The other three are also on at least one other very long; the antennal flagellomeres I-II are not pine species in eastern North America. On the other connate; and the palpi have three or four segments. hand, Cecidomyia candidipes Foote is known exclu- For a key to genera of North American sively from white pine {Pinus strobus L.), although it Cecidomyiidi, see Gagné (1973).^ The larvae are spin- may yet be found on other soft pines {Pinus, sub- genus Haploxylon) in western North America as that region becomes better collected. Cecidomyia larvae are usually easy to find and 'Systematic Entomology Laboratory, c/o U.S. National Museum of Natural History, Washington, D.C. 20560. rear to the adult stage in early spring, although they 2The year in italic after the author's name indicates the reference may not be present on some trees and stands. Full- in Literature Cited, p.9. grown orange larvae, 5-10 mm in length, can be seen in small pitch-filled crevices or large nodules and outside, a spHt develops along the dorsum of the pitch masses (figs. 2-3) in early to mid-April near pupal thorax, and the adult emerges. Larvae of those Washington, D.C. Larvae in twigs brought indoors species that pupate apart from the pitch mass have and placed in plastic bags soon pupate and adults distinctive dorsal abdominal tubercles (fig 27) emerge shortly after. The larvae either remain in the whose function is unknown. Each larva forms a' pitch masses to pupate or leave depending on the white cocoon (fig. 4), which, when formed on a pine species. Those remaining in the pitch pupate in a needle, is fairly conspicuous. The pupa escapes silken cylinder, which effectively separates the pupae through a circular cap at the anterior end of the from the resin. When the adult is fully formed, the cocoon, and the adult then breaks out of the pupal pupa pushes through a thin cap of dried resin to the skin. ^ ^ Genus CECIDOMYIA Meigen Itonida Meigen, 1800: 19. Type-species, Tipula pini De Geer (Co- very large, produced apicolaterally to partially quillett, 1910: 556). Suppressed by International Commission envelop telomere in C. tortilis and C. reburrata; on Zoological Nomenclature {1963: 339). Cecidomyia Meigen, 1803: 261. Type-species, Tipula pini De Geer telomere short or long, variously shaped, setose (monotypic). throughout, setulose on basal two-thirds, striate on Cecidomyia, subgenus Diplosis Loew, 1850: 20. Type-species, distal third; tergum X with fold at midlength, cerci Tipula pini De Geer (Rondani, 1860: 289). triangular; sternum X narrow to wide, simple to Cryptodiplosis Kieffer, 1895: cxciv. Type-species, Tipula pini De deeply lobed; aedeagus simple, long to short, Geer (orig'. designation). Synonym by Kieffer {1913: 211). Retinodiplosis Kieffer, 1912: 1. Type-species, Diplosis resinicola rounded or blunt apically. Female abdomen: Terga Osten Sacken (orig. designation). Synonym by Vockeroth I-VII as for male except VII as long as preceding ter- {1960: 65). gum; sterna I-VII as for male; tergum VIII rectan- Stelechodiplosis Mohn, 1955b: 141. Type-species, Stelechodiplosis gular, with basal pair of trichoid sensilla and scat- magna Mohn (orig. designation). Synonym by Vockeroth tered setae on distal half; sternum VIII not apparent; 1960: 66). ovipositor short, protrusible, with scattered short /4rfw//.—Head as in figures 6-7. Eyes broadly setae laterally and ventrally; tergum X lightly sclero- confluent at vertex, facets closely juxtaposed, hexag- tized, with scattered short setae; cerci with two short, onal. Postvertical peak absent. Antenna with 12 flag- apical sensoria, covered elsewhere with dense, short ellomeres, I and II not connate; male flagellomeres setae. binodal, tricircumfilar; female flagellomeres cylindri- Pupa,—Antennal horns rounded, crested, or cal, their two circumfila connected by two longi- peaked. Pronotum variable, with two pairs of setae. tudinal strands. Palpus four-segmented, except three- Frons with two pairs of setae. Face with group of segmented in C. piniinopis. Wing R5 curved distally, three papillae at base of each palpus. Prothoracic joining C posteriad of wing apex; C broken at junc- spiracles variously shaped, variable within species. ture with R^, Rs weak; M3^.4 fold present; Cu Abdomen covered with minute spicules. forked. Legs usually covered with brown scales, but Larva (figs, 27-28).—Head capsule with very C. candidipes white on distal three hind tarsomeres; long apodemes. Sternal spatula of third instar vari- tarsal claws simple, curved beyond midlength; ously shaped or absent. Papillae as follows: Laterals empodia slightly longer than claws. Male abdomen: on thoracic segments in two groups of three each per Terga I-VI large, rectangular, with approximately side, two of each group with short seta; four fore two rows of caudal setae, a group of lateral setae, ventrals and two hind ventrals, all unhaired; two and scattered narrow scales elsewhere; tergum VII as haired pleurais per side, in some species abdominal for VI except shorter, caudal setal rows