346 F. W. EDWARDS. 



Culex nigritiilus, Theobald, Mon. Cul. i, p. 140 (1901) {nee Zetterstedt). 

 Culex varioannnlatus, Theobald, Mon. Cvil. iii, p. 198 (1903). 

 Culex azoriensis, Theobald, Mon. Cul. hi, p. 210 (1903). 

 Culex quasimodestus, Theobald, Ann. Mus. Nat. Hung, hi, p. 88 (1905). 

 Culex osakensis, Theobald, Mon. Cul. iv, p. 439 (1907). 

 Culex pipiens var. dolionim, Edwards, Entom. xlv, p. 263 (1912). 

 (??) Culex nigritulus, Wesenberg-Lund, Danske Vid. Selsk. Skr. Nat. Math. Afd. 

 (8) vii, p. 131 (1921). 



The distinctions in external characters between the adults of C. pipiens and 

 C. fatigans have been enumerated above. I have found them reliable in sorting out 

 Mesopotamian specimens, where the two species occur together and C. pipiens 

 is fairly constant ; but in the southern and eastern Mediterranean region C. pipiens 

 is subject to so much variation that the hypopygial differences would have to be 

 relied on ; the structure of this organ in C. pipiens is fairly constant, the slight 

 variation that does occur showing usually little or no approach to C. fatigans. 



The examination of a number of mounts of hypopygia of Japanese specimens, 

 however, seems to show that the Japanese race of C. pipiens differs constantly from 

 the European, liaving the second division of the mesosome much broader than usual 

 and the third division not quite so stout, thus being to some extent intermediate 

 between C. pipiens and C. fatigans. Theobald's type male of Culex osakensis, which 

 in 1912 I took to be C. fatigans, belongs to this form, but Coquillet's name pallens 

 is no doubt also applicable, and should be used to designate the variety. It would 

 seem from their figures that Dyar and Knab's Cttlex comitatus, described from 

 California, belongs to this var. pallens rather than to t3^pical C. pipiens, audit is quite 

 likely to have been introduced into California from Japan. In both C. pipiens and 

 C. fatigans a minute basal arm to the tenth sternites may be present or absent. 



A variety of frequent occurrence in the Mediterranean region has the pale bands 

 of the abdomen reduced to lateral spots, either in the female only, or in both sexes. 

 There are also two other varieties worthy of special mention. In North Africa 

 many specimens occur with the mesonotal scales more or less ochreous, and in some 

 the dark parts of the abdomen also tend to this colour, so that it is tempting to 

 assume that we have here an incipient modification in colour to suit desert conditions. 

 I have examined the hypopygium of one specimen so coloured, and have no doubt 

 as to its identity. Theobald has described this variety as C. quasimodesta, but it 

 is doubtful if it is at present more than a sporadic variation. The second variation 

 is in the length of the upper fork-cell of the female. Over the greater part of the 

 range of the species this is fairly constant, but in the Levant and Asia Minor many 

 specimens are found in which the cell is shorter than usual, and little, if any, longer 

 than that of C. fatigans. It seems rather significant that this very region is on the 

 borders of the range of C. fatigans ; the possibility of interbreeding may be indicated, 

 but, against this, it should be noted that such intermediate specimens have not been 

 found in Mesopotamia, where the two species are known to occur together. 



I am indebted to Capt. Barraud for calling my attention to the existence of 

 what seems to be a definite larval variety of C. pipiens in Palestine and Syria. In 

 this form the average number of pecten-teeth is 12, and there seems to be little varia- 

 tion from this ; of 39 specimens critically examined by Capt. Barraud, no fewer 

 than 24 had either 12 or 13 pecten teeth, the number in the remaining specimens 

 varying from 9 to 17. Further distinctions of this Levantine race are the smaller 

 average size, the lighter-coloured antennae, and the shorter average length of the 

 siphon (index about 4-5). 



Capt. Barraud found that in Mesopotamian specimens the average number of 

 pecten teeth was greater and the range of variation more. Out of 27 specimens 

 examined the average number of teeth was 15*7 ; only 10 specimens had either 15 



