THE CRANE-FLIES oF New YorkK—Part I 869 
few cases in other parts of the wing, as in Hoplolabis (Plate XX XV, 83), 
where a strong spur juts into cell 7st M2 from its outer end. 
Adventitious cross-veins, or veins which are inconstant and of sporadic 
occurrence within a species, being in some cases present in one and absent 
in the other of the two wings of a single individual, are rather frequent 
in the Tipulidae, the most notable cases being the genus Cladura (Plate 
XXXVI, 102) as noted by Alexander and Leonard (1912), and the species 
Tricyphona inconstans (Plate XLII, 177) as noted by Johnson (1901). 
The cells— The cells of the wing take their names respectively from 
the veins lying immediately before or above them; in the case of fused 
veins the cell takes its name from the last element of the fusion. Thus 
the cell behind vein R3 is cell Rs, that behind vein M, is cell M,, that 
_behind vein R4+; is cell R;, and so on (fig. 128, 5). When the cells of 
a field are cut by cross-veins, either primary such as r and m or super- 
numerary, the proximal cell is the first and the distal cell. is the second. 
Thus in many crane-flies the discal cell is present, being cut off by the 
m cross-vein at its outer end; and since both cells lie behind vein M+, 
both are cell M2, the proximal cell (discal) thus becoming /st M. and 
the outer cell becoming 2d M2. The same thing is true of the cell R,, 
which in some cases (as in Dicranota, Plate XLI, 167-169) is divided 
into three cells, numbered outward from the proximal (1st Ry) to the 
distal (3d R,). In most cases the wing cells lying proximad of the 
arculus are so small and reduced that they cannot be readily homolo- 
gized; but in the tropical-American genus Peripheroptera they attain 
a remarkable development, occupying in the males of some species from 
one-third to one-half of the entire wing length. The anal angle of the 
Wing is variously developed, being usually prominent in the family Tany- 
deridae (Plate XXX, 1), the genus Antocha (Plate X XXIII, 48), and 
the subgenus Sacandaga of the genus Rhabdomastix (Plate XX XVI, 97), 
and on the other hand being lacking or nearly so in some exotic 
Limnobiini, such as Thrypticomyia and the males of Peripheroptera. 
The stigma.— The stigma is a dark spot or area usually situated near 
the end of vein R, and often bisected by the radial cross-vein. It may 
be either present or lacking in the various species of a genus, and in some 
cases is very large and pubescent, as in the males of the genus Empedo- 
morpha Alexander. 
