C. australis Macquart 1847

Fourth instar larva:   large bathophilus-type larva.  Length about 12-23 mm (fem. 13.7-23 mm; male 12.5-18.7 mm).  Relative length of ventral tubules appears to vary geographically, with the anterior pair generally longer in N.S.W. and S. Aust., but generally shorter in Tas. and Vic. (Ant. fem. 0.76-2.20; male 0.68-1.84 mm: Post. fem 0.84-2.25; male 0.80-2.00 mm).  Anal tubules from 326-680 µm in length, ventral pair often longer, generally about twice as long as wide, but ventral pair may be up to 4.2 times longer.
Head capsule with heavily darkened posterior half to two thirds of gula and wider than mentum width, widest at posterior margin; also heavily darkened frontoclypeus and dark to very dark on other areas of the head capsule.  Oesophageal opening about 93-114 µm long and 3.36-3.75 times wider than deep.
Mentum (Fig. b) with generally rounded teeth; c2 teeth of central trifid tooth well separated from relatively broad c1 (type IIa); 4th laterals reduced below level of 5th laterals (type ii-III).
Ventromental plates (Fig. c) about 242-270 µm wide, 3.4-3.8 times wider than deep and separated by about 0.37-0.48 of mentum width, and 1.1-1.3 times the width of the mentum; with about 41.8 (36-55) striae; VMR 0.28 (0.25-0.32).
Pecten epipharyngis (Fig. a) with about 10-17 sharp, variable teeth, possibly type A
Premandible teeth about equal in length and inner tooth at least 2 to 3 times wider than the outer tooth (lower values due to premandible not lying flat); inner tooth coming to a broad point, outer tooth to a fine point.
Basal segment of antenna (Fig. d) about 2.8-3.8 times as long as wide; AR about 2.51 (2.02-2.39); antennal proportions (µm) 155 : 22 : 8 : 13 : 8.
Distance between the S4 setae about 0.77-0.89 of the FC width and equal or greater than the distance between the antennal bases.
Mandible (Fig. e) with third inner tooth at least partially separated and partially darkened (type II or IIIB), Tasmanian specimens may have a relatively pale tooth (IIIA); about 15.8 (12-24) furrows at base; 13.9 (10-17) taeniae in the Pecten mandibularis, and Mdt-Mat 29 (20-40.5), MTR 0.34 (0.22-0.40).

Cytology:  4 polytene chromosomes with the pseudothummi arm combination AE, BF, CD, G.
Arm G closely paired with a subterminal nucleolus about 20 bands from the heterochromatic centromere, and a BR about the middle of the arm.  There is a nucleolus near the centromere of arm F, at about band group 19.
No inversion polymorphism is known, but there is a sex-linked polymorphism (MD) associated with the centromere of the CD chromosome, such that the females have two homozygous heterochromatic bands, in males these bands are heterozygous (Martin et al. 1980).
Chromosome sequences mapped according to the Keyl (1962) system:
ausA1:    1a-e, 11 - 10, 2c - 1f, 3e - 2d, 8 - 9, 3f-i, 12c-a, 4 - 7, 13 - 19            as oppositus A4
ausB1:     A large puff (group 7) is developed near the middle of the arm, with dark bands (group 8) proximally.
ausD1:    1 - 2, 16 - 10d, 3a-d, 9 - 3e, 10a-c, 17 - 24
ausE1:    1 - 3e, 10b - 3f, 10c - 13                                                                      as oppositus E1, halophilus, etc.
ausF1:    1 - 2a, 10 - 2c, 15c - 11a, 2b, 15d -19(NOR)- 23                                            as oppositus F3 (see Martin (1979)
ausG1:    Centromere heterochromatic, with subterminal nucleolus and BR about middle of arm.

Larva morphologically very similar to those of C. duplex and C. occidentalis.  Separable from both by the difference in chromosome number, and from the latter also by their different distributions.

Pupa:  Large relatively dark exuvia, shagreen large spines central on segment II, expanding laterally to segment IV, then becoming patches of finer spines on segments V and VI, no spines on segment VII, but patch of very fine spines on posterior half of segment VIII.  Cephalic tubules smaller in females and mostly wider at base than the height, while in males the height is greater than the width. The setae of the tubercles were usually missing.  No frontal wart observed, but area not always clear, particularly in females.

Respiratory base tending to kidney shape, about 200-225µm long by 70-90 µm wide; bases of filaments virtually bilobed, HR 2.5-2.8.  Recurved hooks of segment II occupy about 0.70 (0.59-0.79) of the segment width.
L-seta at anterior margin of intersegment of III/IV and IV/V, quite long, but that of IV/V probably shorter.  Pedes spurii B developed on segments II and III, Pedes spurii A large on segment IV but patches of spines on segments V and VI; PSA on IV about 238-286 µm long x 149-185 µm wide and about 0.23 of the segment length.
Some characters given in Table below:

Length (mm)
9.8 - 13.7
9.7 - 11.8
Inner margin wing case (mm)
2.0 - 2.76
2.15 - 2.72
Cephalic tubercles (µm)
 127 - 230
Cephalic bristles (µm)
 c. 30
Recurved hooks on abd. seg. 2
87 - 109
73 - 90
Swim fin filaments (one side)
96 - 149
100 - 133

Caudolateral spur with 10.94 (7-16) spines in female, 9.38 (7-13) in male; sometimes including 1-3 very small basal spines.

C. australis can be readily separated from C. duplex at the pupal stage on the basis of the pupal spurs, in which the spines are closely applied in C. australis but spread in C. duplex.  The pupal spur of C. australis resembles that of C. occidentalis, but has more spines.  There also tend to be more recurved hooks on the second tergite, but with considerable overlap.

Polytene chromosomes published in Martin (1971b), mapped according to the Australian standard system of Martin (1969).  However the sequence given for arm F is incorrect.  Nucleoli and location of C-bands studied by Lentzios & Stocker (1979) and Lentzios et al. (1980).

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Modified: 24 March 2024
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