116 



Lateral tufts of labium short, dense; the inner part consisting of comb-hairs, 

 arranged as a crown around the palatum, covered with soft hairs. Mouth-parts 

 highly remarkable. Mandibles quadrangular with three strong spines before the col- 

 lar; a row of remarkably short cilia from a collar; a row of very strong spines 

 from margin; most of these spines dentated, furnished with strong thorns. Denti- 

 tion: a broad dark plate formed as the forelimb of a talpa with six almost equal 

 teeth; a series of bristles below; process below distinctly furcate with strong hair- 

 tufts on both tips; a group of hairs at base. Maxilla? broader than long, almost 

 without suture; no apex and no tuft of long hairs upon it; fore and inner margin 

 furnished with a coarse covering of very short, soft hairs; a few hairs near the 

 palpe; a short bristle on the foremargin. The palpe well-developed with a few di- 

 gits. Mentum triangular, borders almost straight; median tooth small, about twenty 

 equal teeth on each side. Colour commonly greyish. 



The larva has been described and figured by Meinert (1886 p. 376). Owing 

 to his description of the sipho and pecten I must suppose that he really has seen 

 the larva, but with regard to the description as well as the figures, especially re- 

 lating to the bristles of the head and anal segment, there are such great differences 

 between his and my statements, that I have often supposed that he has unfortuna- 

 tely used a larva of another species to describe these details. Of the frontal tufts, 

 the lower so characteristic with its one long and two short hairs, is, according to 

 his description, the most feebly developed with three bristles; the habitus figure has 

 only one single very long bristle, and the more specialized figure (2) has a very 

 short tuft with three hairs, one of which is really longer than the others; the 

 arrangement of the tufts differs greatly in the habitus figures from the more detailed 

 figure (Fig. 2). On the mandibles (Fig. 7 — 8) he has correctly indicated that the 

 spines of the inner border are dentated, and the figure of the characteristic broad 

 maxilla (Fig. 6) is correct. He has further seen that the species has comb-hairs in 

 the flabellse. On the other hand the dorsal brush of the anal segment is quite diffe- 

 rent from what I have found; the two long bristles are wanting, and the division 

 in two parts is only problematically indicated in the figure. 



Schneider (1914 p. 44) has a more correct figure of the two last segments 

 (Fig. 4). With Eckstein's statement (1919 p. 290) that the pecten consists of "7 

 mehrzahnigen Dornen" 1 do not agree well. 



Biology. The biology of T. annulata is rather remarkable. If in winter we 

 examine the deep frostless cellars of our houses, we find among the numerous 

 C. pipiens a few much larger ones, highly characteristic because of their spotted wings 

 and white ringed tarsi. This is T. annulata, the largest of all our mosquitoes. I have 

 never found it in great numbers; yet it is by no means rare. 



In December 1918 I took twenty imagines and placed them in a little shed, 

 where the temperature in the nights often fell ^below zero ; most of them died but 

 some hibernated. 



Hitherto we have taken it for granted that the mosquito only hibernates in 



