The Crane-Flies of New York — Part I 869 



few cases in other parts of the wing, as in Hoplolabis (Plato XXXV, 83), 

 where a strong spur juts into cell 1st 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 

 XXXVII, 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 R3, that behind vein Mi is cell Mi, that 

 behind vein Ri + b is cell R5, and so on (fig. 128, j). 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 he behind vein Mi +2, 

 both are cell M2, the proximal cell (discal) thus becoming 1st M2 and 

 the outer cell becoming 3d M2. The same thing is true of the cell Ri, 

 which in some cases (as in Dicranota, Plate XLI, 167-169) is divided 

 into three cells, numbered outward from the proximal (1st Ri) to the 

 distal (Sd Ri). 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 XXXIII, 48), and 

 the subgenus Sacandaga of the genus Rhabdomastix (Plate XXXVI, 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 Ri 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. 



