63 



accomplished. The pupae appeared on 20/v and before the 1st of June all 0. lutescens 

 larvae were hatched. The imagines sat in a rather restricted zone round the pond, 

 especially below the Co///i«-bushes. The mosquitoes did not begin to bite before 

 about 15/vi. The ponds were dry till November; contained no 0. lutescens larva? in 

 the winter of 1919, and were open about the first of April. On 16/iv the ponds 

 teemed with 0. lutescens larvae halfgrown, fullgrown on 3 /v, and on l 9 /v the ima- 

 gines were hatched. — In the rainy summer many of the ponds contained water, 

 and in some of them a few 0. communis larva; were hatched. In a few of them 

 there was no water, but the cattle had made deep holes with their hoofs and in 

 these holes there was some water, only about half a deciliter. These holes contain- 

 ed rather few 0. lutescens larva-; the larva? were found on 29/ V n and the imagines 

 were hatched on l/vm. An- 

 other of the ponds got water 

 on 10/vii; larva; appeared on 

 20/vn; they were hatched in 

 my aquaria and gave imagi- 

 nes by 28/vn, but in the pond 

 no larva 1 were developed, they 

 all died off because the pond 

 dried up. The ponds were dry 

 the whole of the autumn, at 

 all events till 15/x. 



I do not know with cer- 

 tainty if we have here to do 

 with a new second brood or 

 only with larva' derived from 

 eggs which have only now 

 got developmental conditions. 



I suppose that the latter supposition is most correct, and that the species in our 

 country normally has one single generation. 



I have further studied the species on the moors south of Arreso. On 20/vi 1919 as I 

 was driving through the forest Neiede Vesterskov, almost bordering the lake, the horses 

 suddenly became extremely nervous. Clouds of large, yellow mosquitoes rushed over 

 them, attacking especially venter and the inside of the thighs. The mosquitoes 

 made any stay in the forest impossible. Some hours later I was driving over the 

 meadows and arrived at the hatching area of the mosquitoes that had attacked me 

 in the forest. This area, too, is in spring covered with water, but in summer the 

 water dries, and only some ditches and pools remain; herds of cattle live here the 

 whole summer. The mosquitoes were probably hatched in one or two weeks; tbe 

 landowners told me that they had even begun to sting; and that every year they 

 stood like clouds over the grass making any stay for people or cattle almost im- 

 possible. They pounced upon us in vast numbers and bit us very severely. 



Textfig. li. The vast meadows at Arresu. 0. lutescens. 



