CYLINDROTOMINA. 291 



the vein b may be considered as homologous to b, in fig. 6, 

 although it appeal's to be merely the prolongation of the first 

 vein. Thus Fhalao'occra, the general appearance, antenna, etc. 

 of which are so much like Trpula, seems also to indicate a trans- 

 ition towards this genus in its venation. And that this interpre- 

 tation of the course of the first vein in Phalacrocera is not 

 altogether arbitrary, is proved by the Korth American Ph. tipu- 

 lina, closely allied to the European species, but in which, never- 

 theless, the first vein ends in the second, as it does in the other 

 Gijlindrotomina, and the branch h is wanting. But there are a 

 few Tipul. longipalpi (for instance DoKchoj^eza) where the second 

 vein has no fork, and then the resemblance to the Cylindrotomina 

 in that portion of the venation is complete. 



3. In all the specimens which I have had an opportunity to 

 examine, the auxiliary vein does neither join the costa ^as in the 

 majorit}^ of the Tip). hrevipaJpi), nor the first longitudinal vein 

 (as in the Tip), longipalpi), but it stops short abruptly, just before 

 the stigma (compare above, the figures 4 and 5) ; some distance 

 before its abi'upt termination, sometimes close by it, the auxiliary 

 vein is connected with the first longitudinal vein by a short, often 

 indistinct cross-vein. Thus, in this important character, the 

 Cylindrotomina hold the middle between the Tip. longipalpA 

 and hrevipalpi. 



We may sum up the preceding examination by saying that the 

 Cylindrotomina, with all the prevailing characters of the Tip. 

 brevipalpi, show important aberrations in the course of the veins 

 in the vicinity of the stigma, aberrations which prove a leaning 

 towards the Tip. longipalpi. The latent affinity to the latter is 

 further proved by the presence of spurs on the tibioe, and by the 

 general appearance ; the coloring of the Cylindrotomina reminds 

 very much of the two principal genera of the Tipulina — Cylin- 

 drotoma of Pachyrrhina, and Phalacrocera of Tipula. 



If I have gone into some detail with regard to the above in- 

 dicated structural homologies, it is not that I attach an absolute 

 importance to them. New forms may be discovered, which may 

 perhaps overthrow the supposed homologies between the venation 

 of Cylindrotoma and Tipula : but the perusal of my statements 

 will, I hope, in one way prove useful to those who may have to 

 describe these new forms ; it will indicate to them the characters 

 deserving to be mentioned in their descriptions, characters which 



