Two new species of Eretmocerus Haldeman (Hymenoptera: Aphelinidae) parasitizing Aleurolobus rhododendri Takahashi and Dialeuropora decempunctata (Quaintance & Baker) (Hemiptera: Aleyrodidae) from Taiwan

Abstract Background Species of Eretmocerus Haldeman develop as primary ecto-endoparasites of whiteflies (Rose and Rosen 1992). Currently, the genus Eretmocerus comprises 86 species worldwide, of which 11 species have been previously recorded from Taiwan (Shih et al. 2015). Despite having been recently revised for Taiwan, two new species are here added to the Taiwan fauna. New information Two new species, Eretmocerus garrywardi Ward sp. nov. and Eretmocerus liangyihchoui Shih sp. nov. found parasitizing Aleurolobus rhododendri Takahashi and Dialeuropora decempunctata respectively, are described. A key to females of Eretmocerus species occurring in Taiwan is provided.


Introduction
Species of Eretmocerus Haldeman develop as primary ecto-endoparasites of whiteflies (Rose and Rosen 1992). Currently, the genus Eretmocerus comprises 86 species worldwide Noyes 2015, of which 11 species have been previously recorded from Taiwan (Shih et al. 2015). The current paper brings the total number of Taiwanese Eretmocerus species to 13.

Survey, collection and identification of parasitoid hosts
A series of surveys were undertaken from 2004 to 2014 for collection of parasitoid host whiteflies, scale insects and aphids in Taiwan (see Shih et al. 2015). Whiteflies were identified by K.C. Chou (Taiwan Agricultural Research Institute) & C.C. Ko from National Taiwan University, Taiwan.

Terminology
Morphological terminology and the format for species descriptions follow Shih et al. 2015. Basic morphological characters for females are: Antenna: length of clava (C), especially relative to its width; length and shape of first funicle segment (F1); length and shape of second funicle segment (F2); length of pedicel (P); length of radicle (R); length of scape (S). Wing: length of fore wing (L), length of marginal vein (M), length of submarginal vein (SM), length of stigmal vein (ST), greatest width of disc (W), especially relative to the longest posterior alar fringe. Mesosoma: length of mid lobe (ML); greatest width of mid lobe (WM); length of scutellum (SC); greatest width of scutellum (WS). Gaster (metasoma minus petiole): length of gaster (G), arrangement of paired setae on tergites 2-6. Leg: length of mid tibia (MT). Line drawings were made using an Olympus BX51 compound microscope located in the Dept. of Entomology, National Taiwan University (NTU), Taiwan.

Depositories
The holotypes and paratypes of the new species are deposited in the Department of Entomology, National Taiwan University, and Taiwan Agriculural Research Institute, Taiwan. Paratypes of both species are also deposited in the Natural History Museum, London, UK.

Description
Female holotype.
Colour. Head and body entirely yellow, wings hyaline. Legs pale yellow except basal margins of mid and hind femora darker.

Male.
Colour. Similar to female, except middle area of mid lobe of mesoscutum and scutellum pale brown. Marginal vein and Submarginal vein pale brown.
Head as female, except interscrobal area circular, fewer setae on vertex, face and occiput. Antenna with 3 segments, clava cylindrical, acutely pointed at apex. Mesosoma as female, except mid lobe of mesoscutum, and scutellum, with strong reticulate sculpture. Genitalia with elongate aedeagus, phallobase present.

Diagnosis
Eretmocerus garrywardi sp.n. can be distinguished from other species in the genus by the following combination of characters: Antennal clava laminate and blade-shaped. F1 ring-like; F2 triangular-trapezoid. Mid lobe of mesoscutum with 6 setae; side lobe of mesoscutum with 2 setae; propodeum elongate. Fore wing with an unusual linear arrangement of setae; marginal vein longer than stigmal vein; marginal fringe more than 0.25x wing width.

Etymology
Named for Garry Ward, father of the first author. Head (Fig. 8). Vertex with 17-18 pairs of setae; face and occiput with transverse substrigose sculpture, interscrobal area vertically strigose; face with 10-12 pairs of setae; supraclypeal area with 13-15 setae; clypeus with 2+2 setae; upper posterior head with 14-16 setae, 3 pairs of long and robust setae present in a row across the head; lower posterior head with 12+12 setae.