146 ME. F. W. EDWAEDS ON OLIGOCENE [vol. lxxix, 



the abdomen is fully extended (I. 17147, H. 468), the eighth 

 segment (especially the stern ite) is seen to be quite large. Several 

 specimens (I. 17147, I. 17148,1.20561) show well-marked pointed 

 cerci. 



Legs. — Very few examples show any remnant of the legs, and 

 the few that do (1. 10068, I. 9685, I. 9454) have not the claws or 

 terminal tarsal segments preserved. These do, however, show traces 

 of scales on the legs. In one (I. 9454), which has the hind legs 

 preserved, it is unfortunately not possible to determine the length 

 of the first tarsal segment. Another fragmentary specimen 

 (1. 10068), probably of this species, shows the tibia and first tarsal 

 segment of one hind (?) leg, the latter being a little shorter than 

 the former. The front femur and tibia are fairly long, equal in 

 length. 



Wings. — These show no divergence from recent species. As 

 mentioned above, the wings in some specimens are rather nar- 

 Tower, and their fork-cells relatively shorter than in others. These 

 .are probably males. A few (I. 9072, etc.) show traces of the 

 vein-scales, much as figured by Cockerell, and many have the 

 fringe-scales distinct. Two specimens (1.9753 and 1.9754, each 

 .represented by one wing only) have the vein-scales exceptionally 

 well preserved ; they are seemingly rather longer and narrower 

 "than in some examples which have only a few remaining, but are 

 most likely the same species, the difference probably being only 

 .apparent. The upper fork- cell has its base slightly distal to that 

 of the lower, and is a very little longer than its stem. The 

 mediastinal vein (So) ends in the costa immediately above the 

 base of the third longitudinal vein (-B4+5) or very little beyond it. 

 The cross-veins are separated by rather more than the length of 

 'the posterior (I. 9221, I. 9140), or by almost double the length of 

 the posterior (I. 9754). 



From the foregoing description it will be clear that the species 

 is not a true Gulex, but belongs to the genus Aedes in the broad 

 sense. The form of the male palpi, the pointed female cerci, the 

 retractile tip of the female abdomen, and the wing-venation, all 

 point to this conclusion. It is very desirable, however, that we 

 •should be able to go farther than this, and ascertain (if possible) 

 the position of the species within the genus Aedes. Recent work 

 has shown that, while the male palpi may be valuable in this 

 respect, the most reliable indications of relationship are to be 

 found in the genital structures of both sexes. According to Dyar 1 

 'two main groups of the genus Aedes are indicated by the structure 

 of the male hypopygium : (1) The first group is characterized by 

 the presence of claspettes (harpagones) ; in this group the claspers 

 are of minor functional and taxonomic importance, and are almost 

 always slender, lightly chitinized, with a single terminal spine. 

 In this group the subgenus Ochlerotatits includes the great 

 majority of the Holarctic forms, and extends through South 



1 'Insecutor Inscitias Menstruus ' vol. vi(1918) pp. 71-86. 



