BY FREDERICK A. A. SKUSE. 839 



" Two sub-aiarginal cells ; usually five, seldom four posterior 

 cells ; discal cell closed ; sub-costal cross-vein posterior to the 

 origin of the second longitudinal vein, usually closely approximated 

 to the tip of the auxiliary vein. Wings glabrous. Eyes glabrous. 

 Antennse 16-jointed. Tibioi with spurs at the tip; empodia 

 distinct ; ungues smooth." (Osten-Sacken.) 



The genus is of universal distribution ; its numerous species are 

 remarkable for their discordant characters, some of which at first 

 sight seem of too much importance to be merely specific, being in 

 many cases common to a natural group of two, three, or more 

 species, yet doubtfully of generic value ; the entire assemblage of 

 groups and isolated species being bound together by a tie which 

 renders dismemberment difiicult and unsatisfactory. Though the 

 species are classified under two sections, — those with four, and 

 those with five posterior cells to the wings, — this division is clearly 

 far less natural than it is convenient ; for some species in one 

 section are found to be certainly more related to those in the other 

 than they are to the species with which they are associated. It 

 also seems impossible to attach more than specific importance to 

 the length of the antennae, which varies tremendously even in 

 closely allied species. Baron Osten-Sacken considers that " the 

 most reliable characters to guide us are those taken from the 

 structure of the male forceps ; but in order to be available, they 

 must be supported by characters supplied by other parts of the 

 organization." Working on this rule, he found it only possible to 

 provisionally admit a few sub-generic divisions which await better 

 definition, and to point out some groups of species which appear 

 allied. 



One species now described, L. aureola, approaches, but does not 

 entirely correspond with, Baron Osten-Sacken's L. recondita and 

 imhecilla group ; and another, L. rostrifera clearly belongs to his 

 L. luteipennis group ; all the other species appear only to add to 

 the perplexity of forms already known, though a few certainly 

 couple together in groups. We must await further discoveries 

 before this genus can be understood, or a satisfactory classification 

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