Nepticula ulmicola, Stigmella, Stigmella ulmivora, Nepticula

Diagnostic description: 

Diagnosis.  The combination of short pale-tipped antenna, strong  metallic lustre on forewing (coppery proximal part suffused with purple at  least along costa) and metallic fascia make ulmivora immediately recognizable.  

Morphology: 

Male.  Wingspan: 4.8-5.4 mm.  Head: frontal tuft dark fuscous to  blackish; scape white or yellowish white; collar dark fuscous; antenna  slightly less than half length of forewing, dark fuscous, distal quarter  distinctly paler.  Thorax concolorous with base of forewing.  Forewing:  area proximal to fascia shining coppery with slight to heavy purple tinge;  fascia postmedial, shining silvery to brassy; shape of fascia variable,  normally narrowed and sometimes obliterated at costa; distal to fascia dark  purple fuscous; terminal cilia concolorous but paler at tips.  Hindwing:  dark greyish brown; with slender, brown androconial scales at dorsum and  costa, sometimes indistinct; androconial scales extending over fringe to  almost one-quarter length of cilia.  Abdomen fuscous. 
Female.  Wingspan: 5.0-5.6 mm.  Antenna distinctly shorter than half  length of forewing.  Hindwing without androconial scales.  Otherwise similar  to male. 
Male genitalia. Vinculum with anterior margin broadly  emarginate;  lateral corners long and pointed.  Uncus with shallow emargination  in hind margin, projections subtruncate, margins more sclerotized than rest  of uncus.  Tegumen about as wide as uncus.  Gnathos with short transverse  bar, long horns and long anterior processes.  Valva triangular, arcuate;  inner lobe very narrow and indistinct; setae on dorsal side distally divided  into two or three much finer tips.  Transtilla with long, triangular sublateral  processes.  Juxta constricted in middle.  Aedeagus about as long as genital capsule; most of vesica covered by large spines and dentate plates. 
Female genitalia. Bursa copulatrix three-quarters length of  abdomen.  Accessory sac rather large, tapering and convoluted distally;  reticulate field absent.  Corpus bursae large and oval, completely covered  with pectinations.  Proximal part of ductus spermathecae broad, with  close-set spines.  Apophyses posteriores and anteriores of approximately  same length, short. 

Associations: 

Host plant: Ulmus spp.  Egg: on underside near a rib.  Larva: bright green.  Mine : very variable depending on  thickness of leaves; mines in sun exposed leaves are short and almost  straight and mines in shaded leaves are long, narrow galleries; deposition of frass varies from a thin central line (in  long mines) to the mine being almost completely filled (in short mines).  Larval exit slit always on leaf-underside.  Cocoon:  leather brown. 

Distribution: 

From NEJ and eastern Denmark; in southern Sweden up  to Vstm.; not in Norway and Finland. - Widely distributed throughout Europe.

Life cycle: 

Voltinism: bivoltine; adults of the summer generation are scarce.  

Citation: 

Description based on Johansson and Nielsen (1990)

Notes on description: 
The different mine forms have caused some authors, in particular Hering (1931, 1932) and Benander (1953), to recognize three species. How- ever, Klimesch (1975b) and Gustafsson (1975) have convincingly demonstrated that only a single species is involved. Nepticula ulmicola Hering. Lectotype ♂ (here designated) Poland: Krosno Odr. 28.iv.1932, Mine on Ulmus campestris, No. 3867 (Hering) (MHUB). Examined by EJvN. Nepticula ulmifoliae Hering. Lectotype ♂ (here designated) Poland: Krosno Odr. 20.vii.1931, Mine on Ulmus campestris, No. 3842 (Hering) (MHUB). Examined by EJvN.
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith