1865.] 235 



joint of the male, on the under side, rather small, and this joint not 

 particularly modified. 



Abdomen long, slender, conspicuously club-shaped at the tip, in the 

 male ; the ovipositor of the female, which I have not had occasion to 

 examine, consists, according to Dr. Schiner, of four foliaceous valves, 

 which in C. distinctissima have a very complicated structure. It 

 seems, however, that this ovipositor belongs to the type of structure 

 common to the whole group of Cylindrotomina. 



The neuration of the wings is, in several respects, different from that 

 of the other Limnobina; the auxiliary vein stops short abruptly, and 

 is somewhat indistinctly connected near its tip with the first longitudi- 

 nal 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 inner section of the second vein ; (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 

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

 discal cell towards the margin of the wing, the anterior one in the Eu- 

 ropean C. distinctissima and in 0. americana has a branch-vein, en- 

 closing one more posterior cell, of which these species have thus Jive 

 instead of four. The European C. glabrata has no such branch-vein, 

 and consequently, only four posterior cells. Still, if we judge by Dr. 

 Schiner's expression, that there are usually five posterior cells in C. 

 distinctissima and four in G. glabrata, it would seem that this charac- 

 ter is not altogether constant. In C. americana the discal cell is very 

 much extended on the inside beyond the small cross-vein, towards the 

 basis of the wing; this does not seem to be the case with the European 

 C. distinctissima. 



The differences between this genus and the two following will be ex- 

 plained under the head of the latter. The relationship of the whole 

 group to Tipula and Ptychoptera has been developed above, in the 

 general remarks on the Limnobina anomala. 



The genus Cylindrotomaw&s proposed by Macquart in 1834 (Suites 

 a Bitffon, Dipteres, I, p. 107) for Limnobia distinctissima, Limnopliila 

 macrocera Say and a Limnobia macroptera, which seems to be an Via. 

 Later (Dipt. Exot. 1,1, p. 67) he added to it Limnobia erytlirocepliala 

 Wied. and L. acrostacta Wied.. neither of which are Cylindrotomae. 

 This mixture of species belonging to quite different genera proves how 

 little Macquart understood the peculiarities of the species 0. distinctis- 



