Pagastia, Makarchenko, 2019

Makarchenko, Eugenyi A., 2019, Review of the genus Pagastia Oliver (Diptera: Chironomidae: Diamesinae) from North America, with description of P. (P.) subletteorum sp. nov., Zootaxa 4664 (1), pp. 115-128 : 124-127

Pagastia (H.) sequax (Garrett)

( Fig. 18 )

Prodiamesa sequax Garrett, 1925: 7 .

Hesperodiamesa sequax (Garrett) ; Sublette, 1967: 305.

Pagastia sequax (Garrett) ; Serra-Tosio, 1971: 80–81; Serra-Tosio, 1976: 136; Oliver, Roussel, 1982: 853; Makarchenko & Makarchenko 2000: 173.

Material. Lectotype ( CNC 7919 . slide number 1): adult male, Canada, British Columbia Province, Cranbrook , 1.VI.1924, leg. C.B.D. Garrett.

Adult male (n = 1).

Total length ~ 4 mm.

Coloration. Dark brown, blackish.

Head. Eyes hairy and slightly extended dorsomedially. Clypeus with 11 setae. Antennae and palps missing.

Thorax. Antepronotum with 5 dorsomedial and 4–6 ventrolateral setae. Acrostichals present but not clearly vis- ible, dorsocentrals ~ 20 (in 2 rows), prealars 17, scutellars ~ 65.

Wings and all tarsi of legs missing.

Hypopygium elongated ( Fig. 18 ). Tergite IX with 23 setae on each side and with a narrow anal point 95.7 μm long, pointed and without apical peg. Laterosternite IX with 8 setae. Transverse sternapodeme 232 μm long. Aedea- gal lobes reduced. Gonocoxite very long, reaching 508 μm; basal lobe small. Gonostylus 213 μm long, narrowest basally, gradually expanding apically, with megaseta 9 μm long. HR 2.38.

Pupa. Oliver & Roussel (1982) recorded that pupae exuviae, collected by Dr. D.R. Oliver in Alberta (Highwood Pass), were passed to Dr. W.P. Coffman for description. This description, however, was never published.

Larva described by Oliver & Roussel (1982).

Remarks. A rare, at least in collections, and insufficiently studied species. Obviously more specimens, of all three life stages, are sorely needed.

Distribution. Canada: British Columbia, Alberta.

Figures

FIGURES 14–18. Pagastia (P.) partica (Roback) (14–17) and P. (H.) sequax (Garrett) (lectotype) (18), males. 14, 18, hypopygium in dorsal view; 15, gonostylus; 16, aedeagal lobes; 17, part of hypopygium without tergite IX. MAl, median aedeagal lobe. Scale bars: 50 µm.