Trifurcula squamatella

Diagnostic description: 

Diagnosis.  Externally most similar to T. immundella, but squamatella  is usually distinctly larger (wingspan usually over 7.8 mm, in immundella  less than 8.1 mm) and immundella has fewer than 44 antennal segments  in ♂ or 40 in ♀.  Fresh material can be separated by colour and also the  broad male genitalia are conspicuous without dissection; the characteristic  valval tips and gnathos can often be seen, simply by brushing away some  scales.  See also T. beirnei.  Male genitalia can only be confused with  those of beirnei, but the gnathos is a very good character.  Female  genitalia resemble T. beirnei, but differ (also from other Trifurcula  species) by large number of setae and much smaller vestibulum.

Morphology: 

Male. Wingspan: (6.6) 7.8-9.8 mm.  Head: frontal tuft yellowish-  white to yellowish orange;  collar paler;  scape white, sometimes with  few brown scales;  antenna with (42) 46-55 segments.  Forewing rather  narrow, uniform greyish brown irrorate, this colour being composed by  three types of scales:  white (almost transparent), with yellow tips and  with grey-brown tips;  these colours tend to fade in old material;  forewing often paler along dorsum and costa;  cilia-line irregular,  terminal cilia yellowish white.  Hindwing: light grey.  Abdomen greyish  brown, anal tufts yellow. Female.  Wingspan:  8.4-10.0 mm.  Antennae with 42-49 segments. Male genitalia.  Very large, more than 0.5 mm long.  Vinculum with comparatively short, rounded, ventral plate.  Tegumen  triangular.  Uncus with medial projection terminally widened and bilobed.  Gnathos very large, central element wide, with almost parallel margins,  terminally rounded;  anterior processes absent.  Valva long, inner margin  sinuate;  ending in long narrow tip, which is curved inwards; transtilla  with straight transverse bar.  Aedeagus with three large cornuti, one  long, straight, one long, curved and one short, curved, with large base. Female genitalia. T VIII laterally swollen, with more  than 100 long setae on either side.  Anal papillae each with about 60  setae.  Hairy terminalia also visible without dissection.  Bursa short,  exceeding segment VII by half its length, covered with minute spines  and pair of indistinct narrow signa, often with incomplete cells.  Ductus  spermathecae with 3 convolutions.

Associations: 

Immature stages unknown.  The species has frequently been  observed on Cytisus scoparius, which is almost certainly the hostplant. 

Distribution: 

Not found in Fennoscandia.  Collected several times in  WJ in Denmark.  -  In the Netherlands from three localities, further from  southern England, southern Germany, France (van Nieukerken, 1987b) and Spain.

Life cycle: 

Voltinism:  adults have been found throughout August and in September.

Citation: 

Description based on van Nieukerken and Johansson (1990)

Notes on description: 
For identity of squamatella and lectotype designation of maxima see van Nieukerken (1987b).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith