( 
) 
7 
} 
f 
REPORT OF THE STATE ENTOMOLOGIST I907 241 
Limnobinae. In this subfamily my material has been more 
abundant. The tribes appear to be founded too often on the pres- 
ence or absence of parts; and usually it is not the presence or 
absence of a part that is most significant, but the form it assumes 
when it is present. Some such characters, however, as spurs and 
empodia, which Osten Sacken conceived to be rudiments, of no con- 
sequence to their possessors he used with great confidence.t Ordi- 
_ narily, these doubtless served him well, but I think they have led 
26, cs Sieand=sarstews Species of Iimnophila, and its first 
to a few incongruous associations of genera. The use of antennal 
characters hitherto has consisted mainly in the counting of their 
segments and is very superficial. Of venational characters, he dis- 
covered that the branching of the radial sector is much more con- 
stant than that of media, but clearly the number of branches of the 
sector and the amount of retraction of Sc?—the characters of 
which he made most use —are characters of degree only, and like 
the waning spurs, and imperfect segmentation of antennae, are 
liable to prove unreliable at critical points. His grouping in sections 
are in the main natural assemblages, for he based them on keen 
scrutiny of all the characters he could discover. He was certainly 
wrong, however, in considering the Limnobiini a group of archaic 
forms [loc. cit. p. 75], for the reduction of branches of the radial 
sector, of segments in the antennae, and of spurs and empodia, are 
all departures from primitive conditions. 
The Cylindrotomini are distinguished from the other tribes or 
sections by a pronounced tendency of R', R? and R® to fuse together 
in one long straight vein tip. Ks is always two branched; Sc? never 
tends to recede toward the wing base independently, but the entire 
tip of Sc often atrophies. Media at its first fork is strongly skewed 
forward, so that Cu! is in line with the median stalk, and when 
veins M! and M? are both present and separate, M! tends to be 
strongly deflected upward at its base (a condition noticed elsewhere 
only in Penthoptera. 
The Limnophilini are a generalized group of Limnobiinae, and 
generally lack the special features of the other sections. ts is three 
branched and typical for this subfamily. Sc is usually forked at 
its tip, except in the aberrant Podoneura and Trichocera. Media 
is three branched except in Ulomorpha and Phyllolabis [| pl. 
— 
1 5ee Osten Sadken, On the atavic index characters, with some remarks 
about the classification of the Diptera. Berl. ent. Zeit. 1894. 39:69-76. 
