8 HENRY F. CARTER. 



well before the middle of the wing. The sub-costa is chitinised and more clearly 

 defined than any other vein ; it is closely apposed to the first longitudinal vein, and 

 owing to the folding of the wing surface in this region, frequently obscures, or partly 

 obscures, the base of the latter. The first and third longitudinal veins (the second is 

 absent) are separate basally, but fuse distally, forming with the extremity of the costa 

 a large, slightly raised, yellowish or pale brown area. These two veins are approxi- 

 mated throughout the greater portion of their course, but diverge slightly before 

 fusing with one another and the costa ; this approximation is usually greatest im- 

 mediately before the divergence mentioned above, and in several species is so close 

 that amalgamation has taken place, with the results that an apparent cross-vein has 

 been formed and a small cell isolated (cf. fig. 8, a-l). The anterior or radio-medial 

 cross- vein is absent. The general course of the fourth, fifth and sixth veins shows 

 little variation ; the upper branch of the fourth vein joins the apex of the wing below 

 the middle, the lower branch is often very indistinct, with an apparently considerable 

 portion of its base, and sometimes its apex, obsolete. At least three vein-like folds 

 (indicated in fig. 7 by dotted lines) are present, and of these the most anterior — which 

 is evidently homologous with the fold just above the upper branch of the fourth vein 

 in other Ceratopogoninae — is relatively strong and conspicuous ; it is, indeed, as 

 strongly marked as any of the veins except the sub-costa, and by most authors has 

 been interpreted as the third longitudinal vein. 



JJ?c 



Fig. 4. L. (?) torrens, Twns., ^ : a, clasper ; b, claws of front leg ; h, antenna (flagellum;. 

 L. kerteszi var. amcricanus, n., : c, claw.s of hind leg (near claw foreshortened). 

 L. bez.VA, Noe, 5 : d, claws of middle leg. 



L. stygius, Sk., <^ : e, claws of front leg (ventral view empodium omitted). 

 I,, siamevsis, sp. n., Q : /, one claw of front leg. 

 L. brasiliensis, Lutz, 9 : g, first tarsal segment of front leg. 

 (a X 770 ; b, c, / x 490 ; (/ X 220 ; ^ x 450 ; g x 260 ; h x 90.) 



As will be gathered from a perusal of the subsequent specific descriptions and from 

 the illustrations referred to above, this account of the wing venation is based upon 

 the study of the wings of females of several species. Among these are included most 

 of the forms previously referred to Tersesthes and Mycterotypiis, and it therefore 

 follows that the venation in these insects is in no way peculiar, and that venational 

 characters which have been advanced for the retention or differentiation of these 

 genera are either of little value or are the results of incorrect observations. 



