58 THE VICTORIAN NATURALIST. 



on I St April. I found that the head of the embryo larva was 

 visible through the egg skin on 22nd April. By 3rd May the 

 eggs were all hatched with the exception of three or four that 

 were deposited last ; and these were, I think, unfertile, as they 

 were still soft, and full of liquid, but showed no sign of 

 containing larvae. 



A curious habit of this insect is that of watching over her 

 eggs from the day they are deposited until the larvae are able to 

 protect themselves. It will be seen that this insect watched 

 over her eggs and brood from the ist April to the i8th May ; 

 and during this time I think the parent insect has taken no 

 nourishment, that is, for 48 days. She has kept watch over the 

 eggs and brood, following the latter about as they devour the 

 leaves. It is well known that social Hymenoptera watch over 

 their eggs after they are laid, but I do not know of single 

 insects outside bees and wasps doing so. I have seen mason 

 flies return, after three or four days, to the cells they have 

 constructed, and, after examining them with their antennae and 

 finding all right, fly away to return in a few days for another 

 inspection. 



The larvae of this saw fly [P. Leivisii) are social. Now, a 

 question worthy of discussion is — Do these larvae remain together 

 for protection, under the idea that "union is strength," or is it 

 the remains of a habit which goes to prove that some time in the 

 past the larvae of this sp. saw fly lived in companies, and were 

 watched and fed by the parent fly, as is common with our bees 

 and wasps. The manner in which this insect looks after her 

 brood points, I think, to a diff"erent manner of rearing to that 

 now adopted by these insects. I find brief mention of Perga 

 Leivisii in Packard's " Study of Insects," page 215, to be seen in 

 Melbourne Public Library. 



CHARLES C. BRITTLEBANK. 



Springvale, June, 18S8. 



MIMICRY. 



By far the most wonderful examples of protective adjust- 

 ments are found where the further disguise of form is added to 

 that of colour, and tp this only is the term mimicry strictly 

 applicable. The pitch of intricate perfection to which mimicry 

 has attained in an undisturbed and unglaciated country like 

 Central Africa is so marvellous and incredible that one almost 

 hesitates to utter what his eyes have seen. Before going to 

 Africa I was, of course, familiar with the accounts of mimetic 

 insects to be found in the works of Bates, Belt, Wallace, and 

 other naturalists ; but no description prepares one in the least 

 for the surprise which awaits him when first he encounters these 



