THE VICTORIAN NATURALIST. 65 



different forms assumed by columnar basalt can be seen. The 

 surface was observed to have some remnants of lava lying in the 

 soil. Below this occurs a stratum of amorphous basalt, exhibiting 

 here and there nodular appearances ; and, underneath this 

 again, the columnar basalt. The columns occupy various 

 angles, from vertical in the centre to a near approach to a 

 horizontal position on either side, the flanking columns inclining 

 towards the centre of the mass. These occur on the west side of 

 the creek, between it and the Stockade wall. Just across from 

 here, on the east side of the creek, a very good example of a 

 pavement of geometric design is seen, caused by fracture of the 

 columns along an approximately horizontal plane, which has cut 

 the columns transversely, showing a section of each individual 

 column ; these are seen to have 4, 5, 6, and 7 sides, the majority 

 being 5-sided. The search for Zeolites, which occur in this basalt, 

 next occupied our attention, and close by we found other curiosity 

 seekers breaking stones in the hope of securing Zeolites for sale. 

 Not far off, to the east, the basalt is again bounded by Upper 

 Silurian strata, up the small gullies of which gold is reported to 

 have been found a few days previously, and several visitors were 

 out to see the place ; but it seems to be unknown whether this 

 gold occurs in the Silurian rocks themselves or has come from 

 some of the Tertiary gravels that occupy the summit of the hill 

 immediately to the east. Returning homewards we supplemented 

 the excursion by spending an hour in examining a private collec- 

 tion of some interesting Australian fossils. — G. Sweet. 



COCOON MAKERS AND COCOON BREAKERS. 

 By Ernest Anderson. 

 (Read before Field Naturalists' Club of Victoria, 1 2th March, 1894.,) 

 One of the first things we learn from entomological works is the 

 universal metamorphosis of insects — that is to say, the transition 

 through the various stages of ovum, larva, pupa, and perfect insect, 

 and a mass of information may be gleaned from different sources 

 on these various stages ; but when a short time since I was 

 seeking for some definite and detailed account as to the manner 

 in which those Lepidoptera which construct compact and hard 

 cocoons free themselves, I could find little but vague generalities 

 on the subject. 



Professor Duncan, in his extremely interesting and popular 

 work, "The Transformations of Insects," speaking of the Lepid- 

 optera, says : — " Immediately after the insect has burst from the 

 pupa case it suspends itself in a vertical position," but on the 

 subject of of how it does burst from the pupa case he is silent. 



Figuier, in referring to the species which construct cocoons, 

 says : — "Those pupse enclosed in cocoons free themselves entirely 



