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absence of real characteristics which might keep the forest-races apart from the 

 house races; the coincidence of the hatching of the summer generation of the house 

 race and its occurrence in the open air on the one side and the appearance of the 

 larva? of the forest races on the other suggests that there must be some con- 

 nection between these phenomena. I think it rather probable that here we have to 

 do with one of those rather rare examples of species, which just now are in status 

 nascendi where new species arise. Some of these races are already now of remark- 

 ably stabile nature. I allude especially to the peculiar yellow very delicate little 

 mosquito C. ciliaris and to C. nigritulus mentioned in the following pages. 



2. C. ciliaris Linne. 



It is with great hesitation and mainly from a biological point of view, that I, 

 in contradiction to all other authors from recent years, again separate C. ciliaris 

 Linne from C. pipiens, to which it has been referred as a synonym. Created by 

 Linne, it was regarded as good species by Zetterstedt, Schiener, Van der Wulfp 

 and Walker. Blanchard, Theorald and all later authors regard C. ciliaris as a 

 synonym for C. pipiens. 



It was separated from C. pipiens owing to its smaller size, its ferruginous 

 thorax and yellowish-ferruginous abdomen. In the structure of the wings, legs and 

 claws there are no differences from the true C. pipiens. 



Every year in the latter part of August and through the whole of September 

 a slender, very delicate mosquito arrives in the Royal Gardens at Frederiksborg. 

 Its head quarters are always in the well-known several hundred years old box- 

 hedges, from which it can be driven out even in October, when a walking-stick is 

 pushed in among the foliage. I have only seen the species here, explored all the 

 ponds in the vicinity, but have not been able to find the larvae. I have therefore 

 never hatched the imagines, and do not know the hair and scale coating of them 

 when newly hatched. 



The mosquito is of a yellowish; faintly brown colour, but the hair and scale 

 coating always feebly developed; mesonotum is covered with a ferruginous uniform 

 coating; the abdomen has almost no scales, appears either unhanded or with faintly 

 developed basal bands almost only developed in the middle line; besides there are 

 no differences from the true C. pipiens. 



I am unable to understand why the box-hedges should year after year, al- 

 ways in the same month of the year, September, be a centre of attraction to de- 

 nuded C. pipiens-forms. Further, as it must be remembered, that during the whole 

 of September I find both males and females in great numbers, and that the speci- 

 mens all differ from the true C. pipiens in the much brighter more ferruginous 

 colour and much smaller size, I cannot see better, but that for the present it must 

 be separated as a species differing from C. pipiens. 



Geographical distribution: C. ciliaris has been recorded from Germany, 

 Austria, Holland and England. 



