Prophylactis megastigmallax Hilton, Young, Halsey, Milla & Kallies, 2025

5.4.1.1. Prophylactis megastigmallax Hilton, Young, Halsey, Milla & Kallies sp. nov.

Figures 1 C View Figure 1 , 2 C, D View Figure 2 , 6 A, B View Figure 6 , 6 D-F View Figure 6 , 7 A-D View Figure 7 , 8 A, B View Figure 8 , 12 A View Figure 12 , 13 A, S 1 A, S 2 B View Figure 13

Description.

Metallic beige heliozelids (Figs 1 C View Figure 1 , 2 C, D View Figure 2 , 8 A, B View Figure 8 ). Wingspan 6.5-8.5 mm (7.4 ± 0.8 mm, n = 18) in females and 6.5-8.0 mm (7.2 ± 0.5 mm, n = 11) in males. — Head: Metallic beige. Eyes red. — Thorax. Grey-brown. — Forewings: Dorsal surface light metallic beige with silver-blue sheen in some light; ventral surface grey-brown. — Hindwings: Dorsal surface grey-brown, slightly darker than forewing; ventral surface light grey-brown; males with silver-grey androconial brush. — Abdomen: Grey-brown dorsally, lighter laterally and ventrally. In females, TVII and TVIII modified to form a Y-shaped pollen-collecting structure (Figs 6 A, B View Figure 6 , 12 A View Figure 12 , S 1 A) approximately twice as long as wide. Scales absent from inner lateral and dorsal surfaces, which are covered in spines. Tip with spines, long setae and a pair of projections shaped like “ onion domes ” (Fig. 6 B View Figure 6 ). — Male genitalia (Fig. 13 A View Figure 13 ). Tegumen truncate with sharply pointed posterior angles; uncus broad and rounded, almost of the same width as tegumen, surface strongly sclerotised along the apical margin with narrow, extended, flattened area that curves inward; gnathos reduced to transverse band. Pectinifer about 1 / 3 of valva length, pecten covered with 15 long sensilla. Phallus apex forming one well-sclerotised hook; phallocrypt with one sharp subapical spine pointing cephalad.

Diagnosis.

Female P. megastigmallax sp. nov. can be distinguished from all other species by the unique “ Y-shaped ” pollen-collecting structure. Males are metallic beige, possess an androconial brush on the hindwing but lack androconial scales on the ventral surface of both wings, have a smooth abdomen and have simple grey forewings that lack a darker golden base. These characters separate it from all other Prophylactis except P. pulchellax sp. nov., which can be distinguished by molecular barcode sequences, the hostplant and location. Prophylactis megastigmallax sp. nov. is found in low-lying winter swamps, while P. pulchellax sp. nov. occurs on rocky slopes.

Etymology.

Derived from the host-plant’s specific name (megastigma) and the suffix “-allax” (ἀλλάξ = reciprocal).

Distribution and Biology.

Prophylactis megastigmallax sp. nov. was found wherever its hostplant, Boronia megastigma , grew, specifically in an area from Collie to the Kalgam River in south-western Western Australia (Fig. S 2 B). Boronia megastigma inhabits winter-wet swamps and its known wild distribution is between Harvey, about 120 km S of Perth, to Cape Riche, about 90 km NE of Albany ( Duretto et al. 2013). Boronia megastigma flowers from the beginning of August to mid-September. When in flower, it is invariably associated with Prophylactis megastigmallax sp. nov. moths, often in considerable numbers. In our experience these moths are by far the most frequent visitors to its flowers. Detailed observations of the biology of this moth (Milla et al., in preparation), show that female moths are the exclusive insect visitors to the flowers and support the conclusion that P. megastigmallax sp. nov. is the obligate pollinator of B. megastigma , which was alluded to over decades but had remained undescribed ( Quick 1963; MacTavish and Menary 1997; Plummer et al. 1999).

Material examined.

All specimens were swept or captured from Boronia megastigma ., unless stated otherwise. — Holotype: ♀ ( MMP 005413 in molecular phylogeny, Fig. 8 B View Figure 8 ). “ 13 August 2014, - 34.38883 ° 116.64430 °, Buranganup Rd, ~ 6 km N of Lake Muir , WA, DA Young ” | “ On Boronia megastigma ”. | “ Holotype ♀, Prophylactis megastigmallax sp. nov., Hilton et al. 2025 ” | “ MMP 005413 ” ( WAM) . — Paratypes (119 ♀♀, 65 ♂♂): - 33.81500 ° 115.70790 °, NW of Vasse Hwy & N of Cundinup Rd, Jarrahwood SF, August 1992, B Bussell (3 ♀♀, 2 ♂♂); - 33.81500 ° 115.70717 °, Busselton-Nannup Rd, 45 km from Busselton, 09 / 09 / 2013, MF Halsey & DA Young (13 ♀♀, 10 ♂♂); - 34.43217 ° 116.60567 °, 4 km W of Bird Observatory, Muir Hwy, Lake Muir, 15 / 09 / 2013, MF Halsey & DA Young (1 ♀); - 34.45042 ° 116.83330 °, Noobijup Rd, Cobertup Reserve, Lake Muir, 13 / 08 / 2014, DA Young (1 ♀, 4 ♂♂); same data except 20 / 08 / 2014 (12 ♀♀, 4 ♂♂); same data as holotype (10 ♀♀, 1 ♂, MMP 005414 in molecular phylogeny); same data as holotype except 15 / 08 / 2014 (4 ♀♀, 7 ♂♂); - 34.82333 ° 116.73833 °, Coalmine Beach Track, Walpole, 19 / 08 / 2014, DA Young (17 ♀♀, 3 ♂♂); - 34.45042 ° 116.83330 °, 5 km W of Bird Observatory, Muir Hwy, Lake Muir 20 / 08 / 2014 DA Young (4 ♀♀, 2 ♂♂); - 33.81320 ° 115.71061 °, Cundinup West, 15 km N of Nannup, 26 / 08 / 2014, DA Young (6 ♀♀, 5 ♂♂); - 34.64495 ° 117.93083 °, Dorper Park Stud, Porongurup 30 / 08 / 2014, DJ Hilton, A Kallies & DA Young (10 ♀♀, 3 ♂♂, MMP 005415 in molecular phylogeny); - 33.40375 ° 116.23790 °, Marble Rd, Collie, 11 / 09 / 2014, DA Young (11 ♀♀, 2 ♂♂); - 34.43889 ° 116.62806 °, Muir Hwy, Lake Muir, 03 / 08 / 2015, L Milla & DA Young (3 ♀♀, 2 ♂♂); - 34.43083 ° 116.60250 °, 2 km W of Bird Observatory, Muir Hwy, Lake Muir, 31 / 08 / 2016, DA Young (3 ♀♀, 7 ♂♂); [NO GPS coordinates] Porongurup, Dorper Park Stud, 30 / 08 / 2014, A Kallies, DJ Hilton, DA Young (15 ♀♀, 8 ♂♂); - 34.70884 ° 118.04265 °, Porongurup, nr Moorialup Rd, 20 / 08 / 2015, on Boronia megastigma, L Milla, DA Young (4 ♀♀); - 34.09305 ° 116.01305 °, ~ 4.5 km ENE Donnelly Mill, DA Young (2 ♂♂); - 33.87343 ° 115.42298 °, Cnr Sue Rd and Margaret Rd, Baudin, 24 / 08 / 2018, DA Young (1 ♀, ♂); - 34.26847 ° 117.47210 °, Mt Barker / Denmark Rd, Mt Lindesay NP, 30 / 08 / 2014, DJ Hilton, A Kallies & DA Young, swept from low vegetation (1 ♀, 2 ♂♂ MMP 004186 in molecular phylogeny).

Additional material.

- 34.70841 ° 118.04289 °, Near Moorialup Rd, Porongurup , 20 / 08 / 2015, L Milla & DA Young (sexes unknown, two whole adults processed for RNA, MMP 003123 in Milla et al. 2020) .