69 



the inner margin a coating of long soft hairs; an inconspicuous row of thorn-like 

 bristles along the margin; palpe well developed with four or five apical digits. Mentum 

 triangular with rather huge median tooth and about 13 small teeth on each side. 



Biology. This peculiar mosquito, easily recognizable by the white scales 

 scattered over the wings, abdomen, and legs, I have for a long time vainly searched 

 for in our country. It has been described as Culc.v salinus Ficalbi (1896 p. 29) from 

 Italy, from the Mediterranean (see Lang 1 920 p. 89), and from England where it 

 seems to be abundant, more especially in the South of England. It is a brackish 

 water species with sea-side habitat; it has very often been found with the larvae of 

 0. caspius and 0. curriei. 



During the regular exploration of the island Amager I always expected that 

 the species would occur sooner or later, but till the last part of August 1920 we 

 never found the species there; nor did all simultaneous exploration of the sea coasts 

 along Roskilde Fjord and various fjords on the east side of Jutland, and the brackish 

 water pools in the southern parts of Lolland and Falster, ever disclose the species. 

 Finally, only a few months (on 20 / v >l 1920) before the work was sent to press, I 

 found the species abundant in pools on the shores of Guldborgsund, which sepa- 

 rates the two islands Lolland and Falster; the pools were often filled with the 

 brackish sea water and contained numerous larva; and pupa 1 . When hatched the 

 pupa? all gave 0. caspius, and I supposed that the larva; would give the same; 

 then suddenly another mosquito with unhanded legs appeared in my cultures, and 

 these were now more thoroughly studied. I then saw that the larva- really did not 

 belong to U. caspius, having all blunt scales and more than one hair in the frontal 

 tufts. Isolated they soon gave the above-named mosquito; a very short examination 

 then showed that the wings and legs were sprinkled with white scales and that 

 the abdomen on the underside possessed a series of black spots. The species was 

 then determined as 0. detritus (Haliday); in the latter part of August samples brought 

 me from Amager and Roskilde Fjord all contained numerous larva' of O. detritus, 

 and many specimens were hatched in the laboratory. It seems that the species in 

 our country has only one generation, the imagines appearing very late; owing to 

 this it had nearly been overlooked. 



Lang (1920 p. 89) supposed that 0. detritus winters as a larva or an egg (in 

 my localities almost certainly as egg) and that the species at least is double brooded 

 "for larva; and emerging Hies have been taken in September'". 



Geographical distribution: O. detritus has hitherto only been found in 

 Italy and England. 



9. O. communis (De Geer). 

 Tab. VIII. 

 Description. Female. Very similar to O. punctor (Kirby). but the scales of 

 head and thorax are darker brown, and the coating of the mesonotum more homo- 



