820 AUSTRALIAN MEGALOPTEtlA OR ALDER-FLIES, 



Of these two families, the Corydalidce, containing the great 

 majority of the genera and species of the Sub-urder, may be 

 again divided into two subfamiHes, as follows: — 



'More than three cross- veins between R and Rs; head quad- 

 rangular CORYDALIN.i:. 



Onh' three cross-veins between R and Rs; head triangular 



Chauliodin.i;. 



Up to the present, only one species of Alder-fly has ]>een re- 

 corded from Australia, viz., Archichauliodes guttiferus (Walker). 

 It is a large, dull- coloured insect, recorded occasionally from 

 many localities in Eastern Australia, but nowhere very common. 

 Both in size and markings, it is ver}^ variable, some individuals 

 having large black spots on the wings (especially on the hind- 

 wings) and others having none at all. The larva is a familiar 

 oljject to naturalists in the Sydney district, being found under 

 rocks and stones in small rocky creeks. In New Zealand, the 

 allied species A. dubitatus (Walker), is very abundant, and its 

 larva is much esteemed as bait for trout, being known as the 

 " Black Creeper," a name that would suit the larva of the Aus- 

 tralian species equally well. , 



Turning now to the smaller family Sialidce, of which no repre- 

 sentatives have hitherto been found in Australia or New Zealand, 

 we find that, of the two known genera, Sialis is Holarctic, reach- 

 ing from Canada through Europe and Siberia to Japan, and 

 down into Asia Minor; while Frulosialis is confined to the New 

 World, one species being found as far south as Chili. 



It would thus appear that, as the SialidcG do not occur in the 

 Oriental region, there is no possibility of their ever having 

 reached Australia from the North. But, in so far as they are 

 admittedly archaic forms, and one species is recorded from Chili, 

 it has to be admitted that there is a bare possibility of their 

 having been able to reach Australia from the South, provided 

 that we admit the truth of the Antarctic Theory so ably cham- 

 pioned by Mr. Hedley. 



That being so, I have always kept in mind the possibility of 

 a true Sialid being discovered in Tasmania, or on some isolated 

 mountain-top in Eastern Australia. I now have the pleasure of 



