MOSQUITOS OF THE PALAEARCTIC RECxION. 307 



Ctdex flavescens, Fabricius, Syst. Antl. p. 35 (1805). 



(?) Culex bipunctatus, Robineau-Desvoidy, Mem. Soc. d'Hist. Nat. Paris, iii 



p. 405 (1827). 

 Culex flavus, Motchulsky, Bull. Soc. Imp. Nat. Moscow, xxxii, pt. 2, p. 503 



(1859). 

 Culex flavescens, Theobald, Mon. Cul. i, p. 410 (1901). 

 Culex arcanus, Blanchard, Les Moustiques, p. 303 (1904). 

 Culex fletcheri, Coquillett, U.S. Bm". Ent. Tech. Ser. 11, p. 20 (1903). 

 Aedes cyprius. Ludlow, Insecutor Inscitiae, vii, p. 158 (1920). 



Although this species seems to be subject to a good deal of variation, it may 

 probably always be recognised by the predominantly yellow-scaled costa and the 

 mainly or entirely yellow-scaled abdomen. In the lightest specimens the proboscis 

 is yellow-scaled except at the tip, where the scales are black ; the palpi and wings 

 are almost entirely yellow-scaled ; the mesonotal scales are rather light yellow ; 

 the thoracic integument is reddish, with a black patch in front from which three 

 black lines extend backwards ; the abdominal scales are all yellow in the female, 

 usually with a median line of dark ones in the male ; the tarsi, though with the usual 

 white rings at the bases of the joints, have the dark portions largely replaced by yellow, 

 except at the tips of the joints. In the darkest specimens the proboscis and palpi 

 are almost entirely black-scaled, the wings are much darker, even the costa having a 

 considerable sprinkling of dark scales ; the mesonotal scales are rather deep brown, 

 contrasting strongly with the white scales of the pleurae ; the thoracic integument 

 is nearly all black ; the female abdomen has rather numerous dark scales at the sides ; 

 and the tarsi are darker. In some males the thoracic scales are almost white, and 

 there are traces of a darker median band. 



It is possible that the two forms above described may represent distinct varieties, 

 or even species, but they appear to intergrade, and males associated with both dark 

 and light females have practically identical hypopygia, the only difference observed 

 being that some (though not all) of the light specimens had a more or less definite 

 hook to the membrane of the claspette appendage (see fig. 7 c). Apart from this 

 the hypopygium is well distinguished by the shape of the side-pieces, the very large 

 basal lobes bearing a strong black spine, and the appendages of the claspettes, which 

 have no membranous expansion on the basal third. 



I at first considered that A. lutescens was identical with the American^, fletcheri. 

 but there are some slight differences: in A. fletcheri the apical lobe of the side- 

 piece of the male hypopygium is smaller, and the mesonotum has a distinct broad 

 dark central stripe. 



This, being a common European species, is much more likely to be Fabricius' 

 C. lutescens than the rare one which Theobald has redescribed as such. Fabricius 

 emphasises the yellow costa and the yellow proboscis with a black tip ; he does not 

 mention the tarsi, the statement that they are dark being due to Meigen, who may 

 have had another species before him. Martini was of the same opinion regarding 

 Fabricius' species, but did not adopt the name ; I consider the identification sufficiently 

 probable for the name to be used. Zetterstedt, Ficalbi and Martini use the name 

 anmtlipes, Mg., for it, but this is certainly wrong, since the abdomen is never banded, 

 as Meigen states is the case in annulipes. Although Motchulsky's diagnosis is very 

 brief, I consider it highly probable that his C. flavus is our A. lutescens. 



Distribution. — Europe, except the west ; Siberia ; extending in a slightly 

 modified form into North America. I have seen specimens from Denmark [Wesenberg- 

 Lund) ; Sweden (Ostergotland, Scania, Boheman, light females) ; Finland (Kuusto, 

 Lundstrom ; Eriksberg, E. J. Bonsd.) ; Germany (Berlin, Wanen, Lichtivardt, 

 Oldenberg, Tetens, females of hght and dark forms ; Radoj, Loew, dark female) ; 

 Austria (Modhng, Pokorny ; Michelstettin, Bischoff ; Sterize, Styria, Mann ; 

 Weyshi, Steiermark, Mann ; males, and females of dark form) ; Hungary (Pressburg, 



