134 DESCRIPTIONS OF AUSTRALIAN MICRO-LEPIDOPTERA, 



For riglitly understanding the process of development a careful 

 comparison of the fauna of other regions is required, and the 

 Micro-Lepidoptera have been as yet very partially studied. It is 

 possible, however, to make a fair comparison with the region 

 which Mr. Wallace has called Palaearctic, so far as it is represented 

 by Europe, and with North and South America to a less extent ; 

 and to make use of a few fragments of positive evidence from 

 other countries, with the following results. I should premise 

 that these minute Micro-Lepidoptera, from their extreme delicacy, 

 fragility, and defencelessness, from their lacking the rapid and 

 powerful means of locomotion of butterflies and large moths, and 

 from the usually very short term of their lives, afford excellent 

 material for the study of geographical distribution. 



The well-marked generic differences of structure, and the fixity 

 of type m most cases, are very conspicuous in these lowest families 

 and are evidences of a hoary antiquity. In no genus is this more 

 evident than in Nepticula, which is represented apparently all 

 over the world in equal proportion, by numerous species which 

 have everywhere an extreme resemblance to one another. Of the 

 other genera in these families Bucoulatrix, Opostega, FhijUocnistiSy 

 Coriscium, and Gracilaria, appear to have also a practically world- 

 wide range. Of some of the other genera, which have but few 

 species, it is not yet safe to say where they may not be found. 

 There is however one extensive genus which is interesting by its 

 entire absence from the Australian region, namely Lithocolletis, of 

 which I could not have failed to find traces if it had existed here. 

 (I may observe here, that the insect described by Newman as 

 Lithocolletis lalagella, (Trans. Ent. Soc, Lend., Vol. Ill,, N. S., 

 300) is certainly a Gracilaria allied to G. caenotheta smd autadelpha, 

 but not accurately identifiable. This genus comj)rises a very 

 large number of species in Europe, and North and South America, 

 and is also known to occur in India ; most forest trees have one 

 or more species attached to them, and of many the individuals 

 in extreme profusion, showing that throughout this range of 



