211 



• Family Securifera. 



Tribe 1. Tenthredinetje (Saw-flies). 



Genus Perga (Leach). 

 Perga eucalypti, sp. nov. ? (PL LXII.) 



These larvae are gregarious, and live exposed on the leaves of the 

 Eucalyptus, on vphich they feed, and when full-grown attain a con- 

 siderable size, from 2 inches to 2\. Of a uniform velvety black, 

 with numerous short stiff white hairs, they bear a general resem- 

 blance to Lepidopterous Caterpillars, easily discernible however by 

 the possession of only six squamous feet, and these large, powerful 

 and reddish. 



Living, as they do, in considerable numbers, huddled together and 

 even one upon another, on the upper as w^ell as the under side of the 

 leaf, they present so striking an object, that the most unobservant 

 must easily recognize the group of larvse depicted in our plate. 



We may also add, that during their repast these pseudo-caterpillars 

 keep slowly moving their abdominal portions, rapping their extre- 

 mities against the leaves, and, if disturbed, arching their bodies in a 

 menacing manner, and emitting from their mouths a viscid matter. 



Oar larvse buried themselves underground in October, forming 

 cocoons of a very strong, brownish texture. The perfect insect ap- 

 peared in the following March, and measured in expanse of wings ly^ 

 inch, the length of the body being \^, of which the head and thorax 

 constituted ^. 



Fig. 1. The head magnified. 



Fig. 2. Antennae. These are short, 6 -jointed, the last joint longest 

 and clubbed ; the whole of a yellow colour. 



The legs : anterior pair two spurs on tibiae ; second and posterior 

 (fig. 3) have similar spurs, with an additional moveable spine on the 

 middle of their inferior side ; the tarsi are 5-jointed, the first four fur- 

 nished with pairs of blunted appendages, with large pulvilli between, 

 the ultimate one terminated by strong claws. 



Fig. 4. x\nterior wing. This has four cubital cells, the second and 

 third of which receive a recurrent nervure, the transverse nervures 

 of the disc ; but the radial cell is not appendiculated. 



Fig. 5. Posterior wing. 



The wings of the live insect are brownish inclining to bronze, but in 

 the cabinet these soon assume a shabby and ragged appearance. Head 

 and thorax have a metallic dark green-red lustre. Abdomen bright 

 shining green ; three large orange-yellow patches on the upper side, 

 one at each base of wings, and one over junction of thorax and ab- 

 domen ; underneath similar patches immediately below and between 

 the legs. 



We have other species of this genus in our possession, exhibiting 

 considerable variations in their larvse, as to size, colouring, and 

 markings ; but they are all uniformly supplied with only six power- 

 ful squamous feet. 



