102 



halfgrown larvae in several holes in October November. In December the holes 

 were frozen, and when they thawed in 1919 in March and in 1920 in Febru- 

 ary, they never contained larvae; I take it for granted that the larva? from the au- 

 tumn have died out in the course of the winter. In 1920 the holes which were ice- 

 covered in February contained no larvae before the first days of April; they were 

 filled with water till June, but no pupae appeared before this month. In August 

 1920 I saw the only sign of a second generation. A large beech was cut down in 

 May; in the stump was formed a hole, and this hole was filled \vith water in the 

 first part of July; during the last days of July I found almost fullgrown larvae 

 which were pupae in the middle of August and have most probably given a second 

 generation in the latter part of the same month. During the whole summer I 

 found larvae of very different size; at a first glance one would think that this must 

 be interpreted as if the mosquito had many generations in the course of the year. 

 I do not think this is the case; in our country the different sizes of the larvae must 

 in my opinion be referred to eggs which have arrived at their natural hatching 

 conditions at different times of the year. 



When the imagines were hatched in my cages, they stung immediately; they 

 had great difficulty in piercing the skin and often tried from ten to twenty times 

 before they got blood. I had hoped that these gorged imagines would lay eggs in 

 the vessels placed in the cages, but this did not occur. 



The eggs are laid in July August and are to be found on the sides of the 

 holes, commonly a little above the water rim. Most probably the eggs are laid at 

 different times and by different females; under specially favourable conditions e. g. 

 in wet summers, in which the eggs are reached by the water rim at a very early 

 date, it may possibly occur that some of these eggs are hatched in the very sum- 

 mer in which they are laid, but I feel quite sure that the main part hibernate as 

 eggs, and are not hatched before the next year, commonly in March April. 



LANG (1920 p. 96) agrees with me with regard to the number of generations; 

 he maintains, as I, that there is most probably only one generation, and that the 

 larvae grow slowly. That this is not always the case, ECKSTEIN (1919 p. 101), has 

 tried to show starting from very careful observations; it seems that he has proved 

 that more than one generation can be hatched in the course of the summer; the 

 number depends upon the number of rainy periods; the first generation takes 36 

 days from hatching of egg to imago, the last only 10. I feel convinced that this is 

 not the case in our country. Whilst in Germany, in the time from 24/m to 23/ v , five 

 series of eggs can be hatched, in Denmark no imagines appear before June; further 

 the high temperatures in tree-holes (21 24 C.), mentioned by ECKSTEIN, have never 

 been found in our country, the temperature most probably never exceeding about 

 15 degrees. 



Geographical distribution: Most probably Finlayia geniculata is widely 

 spread over the whole of Europe; it is unknown from Scandinavia, rare in our 

 country and most probably has a more southerly range. 



