Early descriptions of C. hawaiiensis

Early descriptions of C. hawaiiensis

Original description of Grimshaw (1901)
Grimshaw, P. H. 1901 Diptera. Fauna Hawaiiensis 3: 4-5.

(i) Chironomus hawaiiensis, sp. nov.
Long. corp. male 5, female 5-6 mm.; al. male 3, female 3-3 1/2 mm.

Male. Head and basal joints of antennae yellow, palpi yellowish-brown, plumes of antennae light yellowish-brown, eyes black. Thorax with the ground-colour whitish, almost silvery, in some specimens with a slight greenish tinge, two anterior approximated dorso-central and two posterior lateral abbreviated stripes reddish-brown, the three lines of ground-colour thus left furnished with rather long very pale hairs;
pleurae and scutellum greenish-grey, the latter with long pale yellow hairs, metanotum reddish-brown, halteres pale. Abdomen slender, yellowish-grey, with light yellow hairs, each segment with a triangular basal dark brown spot, the apex of which points backward while the base extends completely across the segment, apical segments almost entirely dark.
Legs light yellow, all the femora with a brown ring near the apex, fore legs except the femora, bare, with the tibiae a little more than half the length of the metatarsi, basal third and tip of tibiae brown, tips of all the tarsal joints likewise brown, intermediate and hind legs long-haired, tips and bases of the tibiae and tips of the tarsal joints brown.
>Wings whitish hyaline, anal angle prominent, transverse vein dark, rest of venation pale.

Female. Similar to the male, terminal joints of the antennae dark and slender, legs almost bare.

HAB. Oahu, Waialua, Koolau range, three males and three females from the beach and coast, February 1893.

Martin Spies examined four of the six syntypes from the British Museum of Natural History and provided the following additional information on two males:
One syntype was missing antennae and foretarsi.
Wing length 2.44 mm and 2.61 mm. AR 3.0. LR 1.70 (Ant Ti 1000 µm; Ta! 1700 µm), other Ant Ti 960 µm. Abdominal marking between that of Figs. 1a and 1c of Spies et al. (2002).
Superior volsellae also similar to those seen in specimens of C. calligraphus.

Plate I. figs. 6 and 7, wing and female antenna.

Adult:

The previous descriptions, Grimshaw (1901), Williams (1944) and Hardy (1960) are not very prescriptive.  They suggest that the major difference from C. calligraphus is the narrow anal point of the male.
Williams (1944), while providing good figures, simply states it to be a chiefly dull greenish brown mosquito-size insect.  He also quotes Dr. R.C.L. Perkins, in the Fauna Hawaiiensis 1, Introduction, as stating that its status as a native insect is very doubtful.
Male:
From from Grimshaw (1901) original description, notes from Hardy (1960) and further examination of two syntypes in the British Museum Natural History by Martin Spies: Length 5 (3.8-4.4) mm., wing length 2.44-3.4 mm)
Head yellowish, palps yellowish brown. AR 3.0
Thorax whitish almost silvery, sometimes with greenish tint, thoracic vittae and metanotum reddish brown (median vitta with a narrow yellow line along the middle, Hardy); pleurae and scutellum greenish-grey.
Abdomen (usually greenish but turns brown after death, Hardy) with a basal triangular dark brown spot with the apex pointing backward (rest of segment yellow to yellow-grey), posterior segments almost entirely dark.
>(Gonostylus slightly swollen at the base and rather slender apically).  An elongate, slender anal point is present, the SVo slender and pointed, from figure perhaps closest to S(f) of Strenzke - Hardy illustration)
Legs light yellow, all femora with a brown ring near the apex, and darkening of the tips of the tarsal segments.  LR under 2 (tibia a little more then half the length of the metatarsus) and, from syntypes) LR 1.70 (Ant Ti 1000 µm; Ta! 1700 µm), other Ant Ti 960 µm.
Wings whitish hyaline, cross vein dark. VR perhaps 0.95 (Gromshaw and Hardy illustrations suggest about 1).
Hardy also illustrates a deformation of the palp in which the fourth segment is swollen and fused with the fifth segment.

Male hypopygium of C. hawaiiensis from Hardy 1960
This figure of the male hypopygium is very close to that of a male identified by BARCODE as a C. calligraphus Ty. 2 (i.e. C. hawaiiensis) male from Hawaii.

Female similar to male, terminal joints of antennae dark. Grimshaw figure would suggest the antennal proportions could be: 10 : 7 : 8 : 6 : 13. AR about 0.45 and A5/A1 about 1.3 (from Williams 1944, the clypeal width could be about 1.3 times the diameter of the antennal pedicel; and the palp segments 2-5 proportions: 3 : 11 : 11 : 19).

Female head (lower left), Pupa (upper left), 4th instar larva (right) and larval mentum (center) of C. hawaiiensis from Williams 1944

Pupa: No data - just an illustration in Williams (1944)(above).

Fourth instar larva: No data, but an illustration of the whole larva (above) that shows it to be a plumosus type, and a small figure of the mentum (center, above) that suggests the fourth laterals are not reduced (type I) (it is likely this is accurate as his illustration of the mentum of Chironomus pauciplumatus (not shown) clearly shows the 4th laterals of that species to be reduced).

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