CYLINDROTOMA. 297 



resemblance to the European species, that the ovipositor has a 

 similar structure. The peculiarities of the venation, compared 

 to that of the other Tipulidae, have been explained in the general 

 remarks on the Cylindrotomina (p. 290) ; the auxiliary vein stops 

 short abruptly, and is somewhat indistinctly connected near its 

 tip with the first longitudinal vein ; the latter, instead of ending 

 in the costa, is incurved towards the second longitudinal vein, 

 and ends in it ; a more or less indistinct cross-vein connects it 

 with the costa ; the second longitudinal vein forms with the third 

 a fork, neither of the branches of which is in a straight line with 

 the prsefurca (a different structure of this fork characterizes 

 Phalacrocera) ; the small cross-vein is always present and not 

 rendered obsolete, as in Triogma, by the contact of the sub- 

 marginal with the discal cell ; the discal cell is elongated, and its 

 inner end is nearer to the root of the wing than the inner end of 

 the submarginal cell ; of the three veins emitted by the discal 

 cell towards the margin of the wing, the anterior one in the 

 European G. distinctissima and in G. americana has a branch- 

 vein, inclosing one more posterior cell, of which these species 

 have thus five instead of four. (Judging by Dr. Schiner's ex- 

 pressions about this character, it seems as if it was not altogether 

 constant, and that occasionally specimens of G. distinctissima 

 with four posterior cells occur ; but this must be a very rare 

 exception.) 



The generic character, as defined above, applies to the Euro- 

 pean C. distinctissima and the American G. americana. Gylin- 

 drotoma glabrata M. and nodicornis 0. S. have been included in 

 the genus, in order to avoid the necessity of introducing a new 

 one (compare above, p. 295.). They differ from the typical species 

 in the following characters : the first joint of their antennas has 

 the usual elongated shape, and is distinctly longer than the 

 second ; the antennas of the male are of an entirely different 

 structure ; the head is more narrowed posteriorly, the thorax 

 less short and differently sculptured ; the tip of the abdomen of 

 G. nodicornis 0. S. is narrower and less conspicuously club- 

 shaped ; the lamella of the forceps consists of three linear, horny 

 styles, connate at their bases, and each with a small knob at the 

 tip ; the ovipositor of the female consists of four broad valves, 

 rounded at the tip, and joined to each other without leaving an 

 open interval between them ; the discal cell is much shorter, and 



