THE SERPENTINE LEAF-MINER By F. M. WEBSTER, In Charge, and T. H. PARKS, Assistant, Cereal and Forage Insect Investigations, Bureau of Entomology INTRODUCTION The serpentine leaf-miner (Agromyza pusilla Meig., fig. i, a) was described in 1830 from central Europe1 without definite locality or host plant. The family to which this insect belongs consists of a group of small flies the larvae of which are largely leaf-miners. Some, however, are known to feed upon scale insects, while Agromyza tiliae Couden2 and A. magnicomis Loew3 are known to make galls on twigs of linden (Tilia americana) and on leaves of blue flag (Iris versicolor), respec- tively. Of the species of economic interest in America Agromyza sim- plex Loew occasionally becomes in- jurious to asparagus4 by mining the stems. In Australia A. phaseoli Coq. seriously injures stems of grow- ing beans,5 while in India stems of FIG. I.—The serpentine leaf-miner (Agromyza pusilla) : a, Adult; b, side view of head ; c, side view young peas are similarly injured by of thorax, showing characteristic color pattern; a species of Agromyza.6 d, dorsal view of abdomen, melanic phase; e, out- line of thorax, showing location of characteristic The habits of Agromyza pusilla as bristles. Much enlarged. (Original.) a leaf-miner of clovers have long been known, both in Europe and America, and its injuries have been recorded by some of the earliest students of entomology. With the rapid increase of alfalfa culture in the United States, especially in the irrigated sections of the West, the work of this leaf-miner as an enemy of forage crops has been more and more frequently called to the attention of the Bureau of Entomology. During the past three years this insect has been the 1Meigen, J. W. Systematische Beschreibung der Bekannten Europäischen Zweiflügeligen Insekten. T. 6, Hamm, 1830, p. 185. 2 Couden, F. D. A gall-maker of the family Agromyzidae. (Agromyza tiliae, n. sp.) Proc. Ent. Soc. Wash., v. 9, p. 34-36, fig. 1, 1907.1908. 3 Thompson, M. T. Three galls made by cyclorrhaphous flies. Psyche, v. 14, no. 4, P- 74. fig- 3, Aug., 1907. 4 Chittenden, F. H. The asparagus miner. (Agromyza simplex Loew.) U. S. Dept. Agr., Bur. Ent. Circ. 135, 5 p., 2 flg., 1911. 6 Froggatt, W. W. The French bean fly. (Agromyza phaseoli, Coqtdllett.) Agr. Gaz. N. S. Wales, v. 22, pt. 2, p. 151-154, Feb., 1911. Also pub. as N. S. Wales Dept. Agr. Misc. Pub. No. 1399. 6Maxwell-Lefroy, Harold. Indian Insect I,ife. Calcutta and Simla, 1909, p. 622-623. Journal of Agricultural Research, Vol. I, No. 1 Dept. of Agriculture, Washington, D. C Oct. 10, 1913 K—1 (59) 6o Journal of Agricultural Research VOI.I,NO.I subject of investigations and observations made by several members of the Section of Cereal and Forage Crop Insect Investigations, and the following results are herein set forth regarding this leaf-miner as an enemy of alfalfa (Medicago sativa) and other forage crops in America. SYNONYMY Mr. J. R. Malloch, recently of the Bureau of Entomology, after making a careful study of specimens from Europe and also of a large amount of material from widely separated localities in the United States, includes as synonyms of Agromyza pusilla the following names heretofore supposed to apply to valid species : A. pusilla Meig., A, pumila Meig., A. strigaia Meig., A. exilis Meig., A. amoena Meig., A. puella Meig., A. pusio Meig., A. orbona Meig., A. blanda Meig. (?), A. dimi- nuta Walker (?), Oscinis trifolii Burg., Oscinis brassicae Riley. HISTORY OF THE SPECIES IN EUROPE According to Schiner, " the larvae mine the leaves of Euphorbia cyparis- sias" the cypress spurge, also called " quacksalver's spurge," which according to Britton and Brown has escaped from gardens to the road- sides and waste places in the Atlantic States. The same authority quotes Bouché as stating of Agromyza amoena Meig. that "the larvae mine leaves of Sambucusnigra, the common European elder." Kaltenbach records observing the larvae of Agromyza trifolii mining in the leaves of Trifolium medium in June and in those of T. repens (white clover) in September. He also says of A. strigata: "The mining larva lives in leaves of Campanula irachelium (bellflower)." Goureau,1 in 1861, records Agromyza nigripes, a related European species, as mining in the leaves of Medicago sativa (lucern), in Europe, and his description of the habits and injury caused by these miners is very similar to that which might be given of A. pusilla and its injury to alfalfa in America. Decaux,2 in 1890, records A. nigripes as mining the leaves of lucern in France, and in the infested area estimates a loss of from 20 to 25 per cent of the crop due to the injury to the lucern leaves by this miner. Groult,3 in writing of A. nigripes in Prance, records the mines during August and September in fields of lucern and states that where large numbers of the mines were present the devastation became noticeable and the injured lucern made poor forage. 1 Goureau, Charles. I^es insectes nuisibles aux arbres fruitiers, aux plantes potagères, aux céréales et aux plantes fourragères. Bul. Soc. Sei. Hist, et Nat. de l'Yonne, v. 15, p. 76-454, juill., 1861. "Agromyza nigripes" p. 385-386. 2 Decaux, François. {Agromyza nigripes Meig.] Ann. Soc. Ent. France, ser. ó, t. 10 [Bul.], p. cevi- cevii, nov. 26, 1890. 3 Groult, Paul. UAgromyza nigripes. I^e Naturaliste [Paris], an. 30 (ser. 2, an. 22), no. 517. P- 219-220, sept. 15,1908. Oct. lo, 1913 Serpentine Leaf-Miner 61 i V)¿9Í ' i lïï« r 1%H' Ah *JäL? k¡ ^ k , o- mw i * JW N*"» • 1 f k Í *jl • u < 4 f i T^Hal* ^LJHEÜ^ < * 3 1 r ,/ s 4 1 s T z " b i.f - - " )■ ■ rK ■ ^ jj\^ip*j w V * i ■^m r 1^•/ ■ 'Í 8 < u < K Mi 0 î ^* Jr. */ * ^ r AT JL ^ K *; í 1 t ii í I il1. * ft tí D * si IS It i ■ ^ \ h # * k^ , - ¿# * /9 « w*«& lo * -¿¡Mj^J' ^ , Íh 1 I 'f "^^S k 1Ö ^ u '*"fw WIM * A T#IÖ i¿ b îi , CI i «r, ■a 0 ."l\® ff 5 m % - t -^iss* i. * 3 N < * ; O < te rftV J3 \% i toa y? f f ä dt l'MiéSktà 1 * ST^!ÍBP %; fü H teSr (0 ^x* 6 #5 ¡t 1 '% < t 1 fejyi* ? * O» >lï|s i d&. * r ^0 •° \L- A >1 à* ;jj s 0 ** ? Eat» i^f * ' I> î IL. * t. C* $ 0 S * * * Î *. ; Ê * V ¡É ■ < & 1% J *i M il p^w^ "5 i • —« h 62 Journal of Agricultural Research Vol. I, No. i Mr. H. S. Smith, formerly of the Bureau of Entomology, noticed dipterous larvae mining leaves of lucern in fields in Sicily, Italy, and France during the spring of 1912, and from a pupa taken in one of these mines, collected in Sicily during the last week of December, 1911, reared Agromyza nigripes. He reports the work of this species in Europe as similar to that of the alfalfa leaf-miner in America with which he is familiar. Apparently the larva can be found mining in the lucern leaves in the latitude of Sicily during the entire winter. DISTRIBUTION OUTSIDE OF THE UNITED STATES Outside of the United States this species has been found in middle, central, and northern Europe—Italy, Sicily, Egypt, England, Scot- land, and Ireland. Its general distribution is shown in the map of the world (fig. 2). DISTRIBUTION WITHIN THE UNITED STATES The general distribution of the species in the United States, excluding Alaska and the insular possessions, extends from the coast region of central New Jersey southward to southern Florida and westward to southern California and northwestern Washington. It also occurs about Hono- lulu, Hawaiian Islands. FIG. 3.—Map showing distribution of the serpentine leaf-miner within (See map of the United the United States. States, fig. 3.) Specimens are in the collection of the United States National Museum from the following localities : Washington, D. C. (Coquillett and Pergande); Foristell, Mo. (Riley); Los Angeles, Cal. (Coquillett); Las Cruces, N. Mex.; Douglas County, Kans.; Flagstaff, Ariz.; Wil- liams, Ariz. (H. S. Barber); Honolulu, H. I.; Iowa; Whittier, Cal. (P. H. Timberlake); Biscayne Bay, Fla.; Texas (Belfrage); Piano, Tex. (K. S. Tucker); Cotulla, Tex. (F. C. Pratt); Victoria, Tex. (Hunter). Specimens in other collections are from the following localities : Ocean County, N. J. (Dr. John B. Smith); Portland, Oreg. (Melander); Moscow Mt. (Melander); Mt. Constitution, Winlock, Port Gamble, Woodland, Palouse, Monroe, and Olga, Wash. (Melander); Pullman, Wash. (Melander and Hyslop); Philadelphia, Pa. (Henry Kraemer); Danbury, Conn.; Blue Hills, Woods Hole, Auburndale, and Chatham, Mass. (C. W. Johnson). Oct. lo, 1913 Serpentine Leaf-Miner 63 FOOD PLANTS IN EUROPE According to Brischke, Brauer, and Kaltenbach the following host plants in Europe are given for Agromyza pusilla and its synonyms: Agromyza pusilla Meig.: Agromyza strigata Meig.—Continued. Spiraea ulmaria (meadow queen). Bellis perennis (garden daisy). Solanum tuberosum (potato). Agromyza trifolii Burg.: Hyoscyamus niger (henbane,hog bean). Trifolium repens (white clover). Galeopsis telrahit (hemp nettle). Trifolium medium (zigzag clover). Stachys sylvantrica (hedge nettle). Agromyza orbona Meig.: Euphorbia cyparissias (cy- Ononis s pinosa (rest-harrow). press spurge). Ononis repens (rest-harrow). Agromyza strigata Meig.: Agromyza variegata Meig.: Campanula trachelium (bellfiower). Colutea arborescens (bladder senna). Taraxacum geniculata (dandelion). Agromyza amoena Meig.: Sonchus oleraceus (sow thistle). Sambucus nigra (European elder). FOOD PLANTS IN AMERICA Besides alfalfa, this species has been reared in the United States from the following plants, given here with the locality, date, and collector: Cabbage (Brassica olerácea): St.