164 Distribution of Moths of the Sub-family Bistonince . 



Mediterranean continent, resulting first in the isolation of the 

 Balearic Islands, then of Corsica, followed by the crumbling 

 away of the lands uniting Malta, Sicily and Greece, culminating 

 in early Pleistocene times in the steady wash of the Aegean 

 Sea into the Black Sea and the consequent separation of 

 Z. flabellaria on all of the many islands it now holds. 



Probably, the last to be cut off thus was Cyprus, which 

 remained connected to Asia Minor far into the Pleistocene 

 Age. 



IX.— THE GENUS MEGABISTON (LEECH). 



Megabiston plumosaria (Leech). Distribution: — Japan, 

 Ussuri District. 



Megabiston plumosaria, although veritably a genuine 

 member of the Bistoninae, presents superficially a most curious 

 compromise between species of the Boarmia consonaria group 

 and the two Lyciae, L. hirtaria and L. ursaria. Irrespective 

 of this, in structure, it combines the characters of Lycia, 

 Amphidasys and Biston. 



In its two pairs of posterior tibial spurs and the armature 

 of the male vesica, it makes a close approach to earlier Am- 

 phidasyd forms, whilst in the furca and other points of contact 

 of Amphidasys and Biston, it resembles both ; and the whole 

 is crowned and toned down by a multiplicity of minor and 

 unobtrusive points reminiscent of Lycia. These latter mar- 

 shalled in line and totalled up reveal that its leaning is on the 

 whole toward this last genus. In a few words, the whole 

 meaning of this melange of relationships is that it is a transition 

 form exhibiting to the enquiring mind what the Non-Boarmioid 

 Bistons looked like immediately after their evolution from 

 the Boarmioid main stem. From it, undoubtedly, Lycia, 

 and therefore its linked up genera, have been built and in a 

 significant way, its status as a pioneer species of future apterous 

 groups is stamped on it by its huge feathered antennae. -{, 



We are thus left with no other conclusion possible than that 

 Megabiston bears somewhat the same relation to Lycia as 

 Nyssiodes does to Poecilopsis and Nyssia, and this judgment 

 is confirmed most curiously by the similarity in distribution 

 between Lycia, Poecilopsis, and Nyssia on the one hand and 

 between Megabiston and Nyssiodes on the other. 



Careful study having revealed the history of the pere- 

 grinations of Nyssiodes, upon that history that of Megabiston 

 hangs as on a peg, for it is to all intents and purposes the same 

 and need not therefore be repeated here. 



We have received three special leaflets from the Board of Agriculture 

 and Fisheries, No. 32, dealing with ' War Food Societies ; ' No. 49, ' The 

 Selection of Wheats for Spring Sowing ' and No. 70, ' The Cultivation of 

 Parsnips.' 



Naturalist, 



