a ae 
REPORT OF THE STATE ENTOMOLOGIST 1907 231 
in figure 14,12, 7, k,l, m. Within the limits of two genera, Dicrano- 
myia and Rhypholophus, as these are at present constituted, both 
occurrences may be found in different species. This is illustrated 
for Dicranomyia on plate 27, figures 3 and 4. But it seems to me 
that the differences of stress must be considerable in. wings so dif- 
ferently veined as are these, and that the disappearance in the one 
case of the cross vein, and in the other, of the base of M® are 
really differences of kind sufficient perhaps to justify generic sepa- 
ration. Obviously the stresses in the wing shown in figure 4 of 
plate 17 would be distributed much as in the wings of the Gono- 
myias shown in plate 24, figures 4 and 5, in which a parallel atrophy 
of the base of M? has occurred. 
The medio-cubital. cross vein is present in a considerable number 
of the more generalized representatives of this family [witness 
Dl, 7, MS. i, BA, Ay B Og joll, WAL, iver, i, AS joll, Gy, iawey, i, A, Al, Il eyavel sess 
accounted for in all the others by the fusion of M, and Cu’ upon 
it. This fusion is never very extensive in the Tipulinae, but it 1s 
usually considerable in the Limnobiinae, and after it occurs the 
deflected portion of Cut looks like a cross vein; and it is so desig- 
nated by some dipterologists. After this fusion is completed the 
deflected portion of Cut may migrate toward the base of the wing, 
to a.moderate extent in Hoplobasis [pl: 23, fig. 5], Trimicra [pl. 24, 
fig. 4], Helobia [pl. 24, fig. 1] and Empeda [pl. 14, fig. 5|—to a 
remarkable extent in Diotrepha [pl. 20, fig. 6]. 
The supernumerary cross veins, whose location has already been 
indicated in the diagram [fig. 24], are distributed in part as follows, 
the names of the cells being those of the veins that bound them 
anteriorly. The one in the costal cell occurs in Ephiphragma and 
several related genera. That in cell R! occurs in Dicranota, Poly- 
angaeus, Peripheroptera, etc. The one in cell R?2 occurs in 
Rhicnoptila, Helobia, Limnophila, etc. The one in cell R? occurs 
in Tanyderus, Polyangaeus, etc. The one in cell R* occurs in 
Tanyderus. The one in cell R® occurs in Cyttaromyia, and gave 
the describer of that fossil considerable trouble. The one that 
occurs in the base of cell R (the first basal cell of some systematic 
dipterologists) occurs as a spur from the base of the radial sector 
in many genera. The one in the middle of that cell occurs in 
an Australian aberrant Limnophila that was figured by Skuse!. The 
one in the apex of that cell occurs as a spur projecting from the 
radio-medial cross vein in Trichocera and from M! in a number 
*Linn. Soc. N, §. Wales. Proc. (2) 4 pl. 22, fig. 25. 
