112 LIFE STORIES OF AUSTRALIAN INSECTS. 



in captivity, but we have reared out Pcrga in such 

 a box described above. 



It is interesting to see the marching of a body 

 of these larvse along the ground in order to pupate. 

 We watched a group of them on the Blue Moun- 

 tains at Clarence. They were the larvae of the 

 large sawfly Pcrga Cauicronii- They were passing 

 over ground covered with the greyish-fawn dead 

 leaves of gum trees. Numerous twigs were 



scattered among the leaves. For two days we 

 watched them — a group of about twenty-five ; they 

 had assumed a greyish-fawn colour, and were 

 travelling along quite close to and partly embracing 

 each other, stopping every now and again to 

 ''tap tap" with their heads. Usually a couple of 

 leaders w^ould tap ! tap !, then they would stop, and 

 at once all would tap ! tap ! with their heads. When 

 touched with a twig they hoisted up their tails. 

 They did not move continuously but would pro- 

 gress in a squirming mass for a few inches and 

 then stop. On the third day they had disap- 

 peared. 



The 'Tear Slug" Sawfly, Sclandria is an intro- 

 duced pest from America. The larvae damage 

 the foliage of cherry, pear and other trees. 



Group II. Petiolata. (Abdomen with petiole or 

 stalk.) 



(i) Parasitic Wasps. 



A Family Chalcidae. 



Chalcid wasps are among the most numerous of 

 the families of the Hymenoptera, but most of them 



