PERGIDAE , SYMPHYTA , HYMENOPTERA
(Photo: courtesy of Viljo Bayard Guilfoil, near Hobart, Tasmania)
These are not true Caterpillars, but are the larvae of a wasp, or more accurately a Symphytan. These larvae are gregarious they are often found in a mass of many individuals on the ground or on a tree-trunk. When disturbed, exude a nasty smelling fluid from their mouths. This latter habit has given them the common name of "Spitfires", although they do not actually spit the fluid, just dribble it. The larvae also are inclined to tap their tails in some form of communication with the group
The larvae are cylindrical and black, with a black head and a narrow pale tail, and are covered in short white bristles.
The larvae are often found feeding on:
The larvae grow to a length of about 4 cms.
The adult insect (it is misnamed as a 'fly') is black with a green or blue sheen, with a yellow meta-thorax, and red bands between some of the segments. The wings are transparent and pale yellow. The male wingspan is about 3.5 cms. The female wingspan is about 4.5 cms.
The larvae and adults of this family are quite harmless to people. They do not sting, as their cousins the communal wasps do.
This species is commonly found as several subspecies in
Sawflies are ubiquitous, being found in :
Further reading :
Lynn E, Fletcher,
Vibrational in a gregarious sawfly larva Perga affinis: group communication of competitive signalling?,
Behavioral Ecology and Sociobiology,
Vol. 61, No. 12 (October 2007), pp. 1809-1821
William Forsell Kirby,
Tenthredinidae and Siricidae,
List of Hymenoptera, with descriptions and figures of the typical specimens in the British Museum,
London : British Museum, Vol. 1 (1882), pp. 19-20, and also Plate 1, figs. 13, 14.
(written 23 October 2015)