12 



and lastly at the anterior corner of the thorax a tuft of from two to five hairs; 

 these frontal hairs are all long, stiff hairs, directed laterally and protruding beyond 

 the brushes; in some species of the genus Ochlerotatus the median tuft consists of one 

 long hair and two or three very short ones; the second tuft often consists either of 

 one or two very short hairs, which may easily be overlooked. The lateral hairs are 

 arranged in two large tufts, occupying the middle and hindangles. As HOWARD, DYAR 

 and KNAB indicate, they are situated on low tubercles and prevented from bending 

 backward by a smal chitinuous plate. Near both tufts very long stiff single hairs 

 are often inserted. On the dorsal side of the thorax we often find a number of 

 small tufts of hair, commonly serially arranged; most probably they very often fall 

 off after the moult; generally they have not been indicated in the figures. 



The Abdomen is long, slender and cylindrical; it consists of nine segments. 

 The integument is membraneous, except that of the ninth segment; still it is much 

 thicker on the dorsal than on the ventral side; between the segments the integu- 

 ment is very thin and delicate; the first segments are always shorter and broader 

 than the following ones, the seventh is commonly the longest; on the lateral bor- 

 ders we find tubercles which support the lateral hairs. As it is well known, the 

 motion of the abdomen is extremely high; the motion of the body is always side- 

 wise, never dorso-ventral ; when the animal is to rise from the bottom, the position 

 of the body is vertical and the body is wriggled sidewise upwards; respiratory 

 movements of the abdomen, as it is well known in the larvae of Chironomidce, 

 Phryganidce, a. o. have never been observed. The six first segments bear long setae 

 on lateral tubercles; the number is greatest on the two* first, on the others com- 

 monly only one or two; on the dorsal side we find the so-called subdorsal hairs, 

 shorter hairs arranged in two series, and most strongly developed from the third to 

 the sixth segment. They are often wanting; mostly their number is two; in our Danish 

 species they are generally rather inconspicuous and are well developed only in one 

 single species, the one of the tree-holes F. geniculata ; further, fairly well in the Danish 

 species of genus Culex especially C. nigritulus. In F. geniculata every segment, from 

 the first to the seventh, bears three pairs of setae, an anterior, a median and a 

 posterior one; the median pair is best developed and consists of four hairs in 

 stellate arrangement. Owing to these groups of hairs the whole larva has a very 

 hairy appearance. 



According to drawings and descriptions of tropical larvae it seems that luxuri- 

 ous development of subdorsal hairs and hairs upon the thorax, mostly in stellate 

 arrangement, is a very common trait in larvae living in tree-holes and in water 

 reservoirs in Bromeliaceae and other plants. - - At the base of the lateral hairs, 

 groups of shorter hairs are often to be found. The development of hairs upon seg- 

 ment seven is not so luxurious as on the preceding segments. 



The eighth segment is short and bears dorsally the sipho or respiratory 

 tube; it bears three hair-tufts, one dorsally, one ventrally and one posteriorly in the 

 cleft between the sipho and the anal segment; long stiff single hairs in varying 



