516 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



species) and with a distinct apical articulated appendage or filament 

 (reduced to a bristle in dismnilis (Leicester) and its related species). 

 Female: Eighth abdominal segment rather large, only slightly re- 

 tractile (basal membrane of eighth segment less than 0.4 as long as 

 eighth sternite) ; eighth st«rnite large and usually at least somewhat 

 compressed laterally. Cerci short. Postgenital plate reaching 0.6 

 or more of distance to the apex of the cerci. 



Larva. — Extremely varied, but usually having in common the fol- 

 lowing few characteristics: Siphon almost always with an acus at 

 level of pecten teeth. Anal plate without acus, always incomplete, 

 nearly always with spines or spicules on posterior lateral margin. 

 Ventral brush usually with 8-12 tufts, usually borne on a sclerotized, 

 barred area. Habitat primarily of three types: a, The water-holding 

 spaces of living plants ; b, tree holes and bamboo stumps ; and c, rock 

 holes in stream beds. A few species breed in the water collected in 

 fallen leaves and other water-holding plant remains. A number of 

 species have been found occasionally in artificial containers. A. togoi 

 (Theobald) is found commonly in brackish rock pools along sea- 

 coasts. A. alhoannulatus (Macquart) and A. occidentalis (Skuse) 

 have been reported from brackish marshes. 



Distribution. — This very large subgenus has a world-wide distri- 

 bution, being absent only from the northern rim of the Holarctic 

 region. However, it has attained its greatest development in the 

 Oriental region. 



Relationships. — ^Morphologically this subgenus is most closely re- 

 lated to the subgenus OchJet'otatus (and quite probably derived from 

 a common stock), the only essential differences being the absence of 

 a distinct basal lobe on the basistyle in most species, and the short- 

 ness of the cerci and of the basal membrane of the eighth abdominal 

 segment in the female. Also, the subgenus in general is more highly 

 ornamented than is Ochlerotatus., and the larvae are found only 

 rarely in ground pools (as are the larvae of nearly all the species 

 of Ochlerotatus). As yet the larval morphology is known adequately 

 for too few species to permit a decision as to whether valid separa- 

 tion characters exist in that stage. As is to be expected, some aedine 

 species occur that are annectant between these two subgenera, and 

 it will not be possible to settle the position of these definitely until 

 much more morphological and biological data are available for them. 



The Neotropical subgenus Eowardina Theobald is also closely 

 related to F inlay a^ differing from it according to Edwards (1932) 

 only in the simple claws of the female, the less prominent eighth 

 sternite of the female abdomen, and the less developed claspettes 

 of the male genitalia. However, in this last respect the species 



