REPORT OF THE STATE ENTOMOLOGIST I907 23 1 



in figure 14, i, j, k, I, 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 

 pi. 17, fig. I, 2, 4, 5. 6 ; pi. 14, fig. I, 2 ; pi. 16, fig. i, 2, 4, 6] and it is 

 accounted for in all the others by the fusion of M3 and Cu^ upon 

 it. This fusion is never very extensive in the Tipulinae, but it is 

 usually considerable in the Limnobiinae, and after it occurs the 

 deflected portion of Cu^ looks like a cross vein ; and it is so desig- 

 nated by some dipterologists. After this fusion is completed the 

 deflected portion of Cu^ may migrate toward the base of the wing, 

 to a moderate extent in Hoplobasis [pi. 23, fig. 5], Trimicra [pi. 24, 

 fig. 4], Helobia [pi. 24, fig. i] and Empeda [pi. 14, fig. 5] — to a 

 remarkable extent in Diotrepha [pi. 29, 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^ 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 firstbasal 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 

 a'n 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. S. Wales. Proc. (2) 4 pi. 22, fig. 25. 



