38 



Arreso I never found the larva, but with regard to the above-named ponds (Mo- 

 chlonyx-pond I), the Bidens-ponds at Clausen's brick-factory and the ponds in 

 Stenholtsvang I had better luck. In the time from 20/ v to 31/y I found a very 

 little larva here, at once recognisable as something peculiar by its almost black 

 head and white abdomen. The larva grew no larger, and on 3l/ v A. cinereus was 

 hatched. About 20/Vi all the ponds were dry; none of them got water again 'before 

 the last fortnight of October. On 20/y, when the larvae were found, the depth of the 

 ponds was only about a decim. In the last part of June 1919 I saw very little of 

 the imago, but on my return to Hillerod in September I found the imago in enor- 

 mous swarms over the same ponds where they were hatched in the spring. Large tufts 

 of Cyperacece covered the ponds, which were wholly dry; sitting on one of the tufts 

 in hope of observations relating to the egg-laying process of 0. cantans, I found 

 my hand covered with a number of these very small vampires. They were deep 

 down in the Cyperacee-tufts, crawled more than they flew; after having sucked 

 themselves so full that they resembled little blood pearls, they were so thick and 

 so heavy that their power of flight was only very slight. Many of them which 

 were caught in my vessels, only crawled and did not try to fly. The sting was 

 almost imperceptible and they had great difficulty in getting blood, the skin being too 

 thick; afterwards, as my hands had got more than fifty punctures, it was covered 

 with a common purple colour and rather aching. On %/iv I only found a few 

 specimens but on lo/ix all had disappeared, and I did not see them any more this 

 year. In 1920 I got the larvae in the same ponds in May, and in July I found the 

 species on the island Lolland. The same observation which I had an opportunity of 

 making that year, I had made the year before at Arres0; the mosquitoes sit deep 

 down in the grass, and do not fly up before they are disturbed by some one 

 walking through the grass. They attack only that part of the body which is 

 moving through the grass, the legs, when walking, and the hands when they are 

 held down in it; this was the case in the brightest sunshine and in twilight about 

 7 o'clock. Especially in the forest it was very remarkable that I never saw them 

 flying; if I sat only a few meters from the pond, I was fiercely attacked by 0. can- 

 tans, but not by a single A. cinereus. Only when I placed myself in the centre of 

 the pond, on one of the tufts of Cyperaceae, the attack took place. 



Having never been able to find the males in Nature, I have only observed 

 them in my hatching-cases. I have got the impression that this tiny mosquito 

 is much more bound to the ground than our other Culicidae. The difficulty with 

 which they got blood seems to indicate that blood can only be sucked from animals 

 with rather thin skin. I suppose that small rodents and insectivores are perhaps 

 their principal prey. 



The life-history of A. cinereus is in our country most probably as follows: Males 

 and females die off before autumn; the males most probably already in June 

 July; the larva stage is extremely short, only from eight to ten days; the pupa- 

 stage lasting normally only a few days; the species hibernates only as egg; the eggs 



