268 THE ENTOMOLOGIST. 



Eetween the years 1905 and 1914 my friend, Mr. Jansou, and I 

 must have seen in the Forest many hundred cristana, and he 

 agrees with me that certainly the majority of these were the form 

 I have ventured to name and describe above. 



78, Parkhurst Eoad, Holloway, N., 

 October 19th, 1917. 



PERONEA CRISTANA : ITS LIFE-HISTORY, HABITS 

 OF THE IMAGO, DISTRIBUTION OF THE VARIOUS 

 NAMED FORMS, AND SOME SPECULATIONS ON 

 THE PRESENT TREND OF ITS VARIATION. 



By W. G. Sheldon, F.E.S. 



(Continued from p. 250.) 



There are two features that are apparent immediately one 

 commences to study the variation of P. cristajia. The first of 

 these is that, whilst the majority of the forms to be found in 

 each locality are identical, in each there are quite a number that 

 are peculiar to it, or that are abundant or frequent in it, and 

 rare elsewhere. 



The second point is that there has been a great change in the 

 forms to be found, at any rate in certain localities, and probably 

 throughout the species' distribution, during the last twenty or 

 thirty years ; certain forms that were obtainable then do not 

 seem to occur now, and, on the other hand, a large number of 

 new forms have appeared ; many of these are quite common, and 

 in two cases the new form has outnumbered any other to be found 

 at the present time. 



These facts being apparent, I have thought it desirable to 

 place on record the present position of the species, so far as its 

 variation is concerned, by giving lists of the forms to be found 

 in its three principal localities — the New Forest, Epping Forest, 

 and Folkestone — to the extent that I have been able to compile 

 them. 



These lists will accomplish two objects — firstly, they will 

 inform the student what aberrations are to be found in each of 

 these localities ; and secondly, what is much more important, 

 they will constitute a record of the present stage the variation 

 of the species has reached, from which it will be possible to trace 

 and establish future developments and their significance. 



I will first deal with the variation in the New Forest, following 

 with that in Epping Forest, and finishing with the Folkestone 

 aberrations. 



The specimens in the first of these lists have been either 

 captured or observed by myself. There are in the New Forest 

 quite a number of habitats of P. cristana, but my specimens, in 



