Hilarempis argentifera Bezzi, 1909

Rafael, J. A., 2012, Revision of Neotropical species of Empididae (Diptera) described by Mario Bezzi. VIII. The species described in Hilarempis Bezzi, Zootaxa 3189 (1), pp. 56-68 : 57-58

Hilarempis argentifera Bezzi

( Figs. 1–10 , 70 )

Hilarempis argentifera Bezzi, 1909: 371 ; Collin 1933: 110; Smith 1967: 33 (catalogue); Yang et al. 2007: 238 (catalogue).

Diagnosis. Dark brown to black; palpus, legs and halter yellow; frons setose; face glabrous; proboscis around 0.75 length of head height; acrostichal setae biserial; scutum with four darker longitudinal bands; fore tarsomere 1 not swollen; abdomen silvery.

Re-description. Holotype female. Body 5.5 mm; wing 5.7 mm long. Head ( Fig. 1 ). Dichoptic; ommatidia subequal. Frons ( Fig. 2 ) grey pruinose, as wide as ocellar tubercle, slightly higher than greatest width, subparallelsided, with short distinct lateroclinate setae, with 6–7 setae at inner row and 2 at outer row. Face as high as frons, but wider, divergent at ventral margin, grey pruinose. Palpus ( Fig. 3 ) yellow, slender, with distinct clear setae, except for few robust elongate black setae. Proboscis ( Fig. 1 ) around 0.75 head height, labrum black, shiny. Ocellar tubercle slightly protruding, ocelli reddish glassy; anterior ocellar seta robust, divergent, and 3–4 short, aligned, distinct posterior setae. Antenna ( Fig. 1 ) with scape and pedicel brown to yellow, postpedicel velvety matte black, 1.5X longer than length of scape and pedicel combined and around 2.2X longer than apparently two segmented stylus. Segment 1 of stylus apparently masked by segment 2, segment two around 0.25 postpedicel length and slightly longer than thin segment 3. Postcranium ( Fig. 4 ) brown, densely grey pruinose, setae of upper half black and more robust than slender and white setae of lower half; postocular setae medium sized as shown in Fig. 4 ; vertical setae subequal to adjacent postocular; occipital setae multiserial, misaligned. Supracervical plate with 1–2 short setae dorsally. Gena and postgena with slender white setae.

Thorax ( Fig. 5 ). Dark brown to black, grey pruinose. Postalar lobe slightly yellowish-brown; scutum with dark longitudinal band between acrostichal and dorsocentral rows and between dorsocentral and supra-alar rows, latter band less conspicuous. Chaetotaxy: 4 black antepronotals, lateral more robust; around 15 subequal, clear postpronotals, except 2 dark posterior setae slightly more robust; 5–6 slender, white proepisternals; around 15 slender, white proepimerals; distinct biserial acrostichals with incomplete internal row, posterior setae damaged; dorsocentrals longer than acrostichals, uniserial medially, misaligned anterior and posteriorly where they appear to be biserial, posterior setae more robust, notably latter; 5–6 short intra-alar presuturals, one of them slightly more robust and one placed near transverse suture; 2 intra-alar postsuturals; 4–5 aligned supra-alar presuturals, posterior setae more robust; 4 aligned supraalar postsuturals, latter stout; 3 robust notopleurals and several slender; 1 robust postalar, 1 short and slender placed anteriorly; 2 scutellars, apical probably convergent or crossed.

Legs ( Figs. 6–8 ). Yellow, with grey pruinosity more distinct on coxae and femora; trochanter with small apical black spot ventrallly, setae short, some of them more robust and black. Fore tibia ( Fig. 6 ) with 1 basal dorsal seta, 1 posterodorsal on basal third, 1 anterodorsal on middle third, 1 posterior, 1 apical anterodorsal, 2 posteroventrals on distal third. Mid tibia ( Fig. 7 ) with 3 anterodorsals, 2 on basal half and 1 distal and 3 posterodorsals, 1 submedian, 1 distal and 1 slender between them. Hind tibia ( Fig. 8 ) with 6–7 dorsal setae, 2–3 basal more slender, 3 anterodorsals, 2 on basal third and 1 apical; 5 anteroventrals, with 2 on middle third and 3 on distal third, 2 of them set closely together; hind tarsomere 1 with 1 dorsal and 1 ventral seta, both placed near base. Fore tarsomere 1 not swollen, narrower than tibia, about 0.5X length of fore tibia.

Wing ( Fig. 70 ). Hyaline with brown veins; costal vein with 1 robust basal seta (not illustrated in figure); pterostigma tenuous, yellow, occupying apex of costal cell and part of cell r 1. A 1 almost entirely evanescent. Halter yellow.

Abdomen yellow in certain angles, distinctly silvery grey pruinose; setae clear, more slender laterally on anterior tergites. Sternites yellow.

Terminalia ( Figs. 9–10 ). Brown, slightly grey pruinose. Tergite 8 shorter than sternite 8 ( Fig. 9 ); tergite 10 elongate; cercus short, slightly acuminate distally.

Male. Unknown.

Geographic distribution. Chile, Valparaiso.

Material examined. HOLOTYPE ♀, “ CHILE [Valparaiso], Quillota , 20.ix.1902 [1000 m]”.

Holotype condition. Left wing missing; right wing on microslide; terminalia in small vial with glycerin, highly cleared.

Discussion. Hilarempis argentifera apparently belongs to a group together with H. dolosa Collin, 1933 , H. facilis Collin, 1933 and H. propinqua Collin, 1933 , all sharing four longitudinal bands on the mesonotum, dorsocentral setae more than uniserial and female cercus downcurved. It differs from all of these species by abdominal tergites yellow from certain angles and sternites yellow. Using the key in Collin (1933), the female specimen of H. argentifera runs to couplet 18 of H. dolosa . It differs from the latter species by the postpedicel 3.1X as long as deep at widest part (2.0X in H. dolosa ), 2.5X in H. facilis and 1.5X in H. propinqua . The proportion between postpedicel and stylus is rather identical in all species cited above. One other more reliable character that can be compared among these four species was used under the H. dolosa description when comparing this species with H. facilis and H. propinqua ( Collin 1933, p. 127) , namely abdomen silvery grey pruinescence absent in H. dolosa and H. facilis , present in H. propinqua and H. argentifera . Based on characters presented here H. argentifera is not conspecific with species described by Collin.

Figures

FIGURES 1–10. Hilarempis argentifera Bezzi, holotype ♀. 1, head, lateral view; 2, frons, frontal view; 3, palpus, lateral view; 4, postcranium, posterolateral view; 5, thorax, dorsal view; 6, left fore leg, posterior view; 7, left mid leg, posterior view; 8, left hind leg, anterior view; 9–10, pieces strongly cleared with edges rather unclear; 9, tergite and sternite 8, tergite and sternite 10 and cercus, lateral view; 10, sternite 8, sternite 9 and cercus, ventral view. Abbreviations: ce = cercus, T = tergite, St = sternite. Scale bars: 1, 6–8 = 1.0 mm; 2–5 = 0.5 mm; 9–10 = 0.2 mm.

FIGURES 70–75. Wings. 70, Hilarempis argentifera Bezzi, holotype ♀; 71, H. barbatula Bezzi, lectotype ♂ (pres. desig.); 72, H. carinata Bezzi, lectotype ♂ (pres. desig.); 73, H. elegans Bezzi, holotype ♂; 74, H. gymnaspis Bezzi, lectotype ♂ (pres. desig.); 75, H. xanthocera Bezzi, ♀ specimen from Peru.