290 
are objects to much variation. In a following paper I shall try to 
elucidate this point more thoroughly; in the” present paper I shall 
restrict myself to the following short remarks. The two lateral 
lobes arise as a keel on each side of the median lobe; they are 
covered with long yellowish hairs on the outer and inner surface. 
When the flabellæ are expanded but at rest, the hairs of the outer 
side form two excavated, cup-shaped hair-brushes; their length is 
very different in the different species. Those of the inner side 
form the two hair-brushes which are adjacent to the hair-brush of 
the palatum and converge into a point, situated a little below the 
hair-brushes of the epipharynx (fig. 12 f); the keels of the lateral 
lobes distinctly separate the two hair-brushes of the flabellæ from 
each other and are visible, when the organs are expanded but at 
rest, as two conspicuous lines. When the organ functionates, the 
two outer hair-brushes are rhytmically and contemporarily struck 
inwards; simultaneously with this motion the inner hair-brushes 
are incessantly raised and lowered. By means of this motion the 
water with its contents of microscopical nutritive organisms and 
particles of detritus is hurled down into the buccal cavity; the 
particles are caught by the inner hair-brushes of the flabellæ and 
then seized by the mouthparts. 
The labrum of Mansonia differs but very little from the typé 
described above; the median lobe, probably a little more promi- 
nent than in the Culeæ, is especially along the borders fringed by 
long soft hairs reaching to and partially covering the epipharynXx; 
the outer hair-brushes of the flabellæ are very large and more? 
luxuriously developed than in any of our Danish Culex-larvæ; the 
apodemes supporting the flabellæ are shaped in accordance with 
those of -the Culex-larvæ, but are at the whole weaker and con" 
sisting of chitin of a lighter colour. 
The mandibles (fig. 13) are not very much different from those 
of the Culex-species, especially of C. ornalus; but, as far as I am 
aware, the structure and the function of these organs are not suf- 
ficiently understood. The border turning inwards is furnished with 
complexes of hairs with very different appearances and functions. 
Uppermost we find here by Mansonia three long and one shorter 
stiff, curved, thorn-like bristles (the comb-teeth); they are movably 
inserted on the mandibles, and constitute the combing part of the 
