876 CHARLES Paut ALEXANDER 
valves may be very much reduced, as in Tipula serricauda. The ovi- 
positor in Tanyptera (fig. 131, B) is normal, but the terminal abdominal 
segments are greatly narrowed and produce a saber-like appearance. 
SEXUAL DIMORPHISM 
Besides the differences between the two sexes in the shape of the 
antennal segments, already discussed, there are many other structural 
differences. In some species the eyes of the female are much smaller 
than those of the male, and in the latter the eyes may be contiguous 
(holoptic) or approximated. In species with elongated rostra, such as 
in the genus Geranomyia, the rostrum of the female is often much 
shorter than that of the male. The legs of the female are in some cases 
shorter than those of the male. The wings of the females of many species 
in widely separated tribes are often reduced so as to be incapable of 
flight; in some forms (Empedomorpha) the stigma of the male is much 
larger than that of the female; in T7pula armatipennis of southern Brazil, 
the wing of the male is armed with an acute spur above the stigma; many 
other species have the costal region strongly incrassated; in the genus 
Peripheroptera, with the greatly enlarged cells before the arculus described 
elsewhere, these cells are much smaller in the female than in the male, 
and the anal angle of the wing is more prominent. 
Color dimorphism is found in the species of Ctenophora and Tanyptera, 
the specific limits of which are very poorly understood at present. In 
at least three eastern-American species of Tipula (T7ipula fuliginosa, 
T. annulicornis, and T. taughannock), the males are light yellow, while 
the females are from dark brown to brownish black and appear to be 
very different insects. 
As a rule the females are larger than their mates, but in some species 
(Teucholabis, Hriocera longicornis, and others) the male sex is the larger. 
HAUNTS 
The various species of Tipulidae are, within rather broad limits, con- 
fined to certain definite haunts or ecological situations. Some species are 
very closely restricted by their habitat, while others occur ina great 
diversity of situations. There is no crane-fly that can be called cosmo- 
politan; Helobia hybrida is nearly so, ranging, as it does, over most of 
the New World, the Palaearctic regis», and southward into the: Oriental 
