766 CHARLES PauL ALEXANDER 
The dominance of the Cylindrotominae (genus Cyttaromyia) in the 
Eocene and Miocene of the North American fauna has already been 
mentioned. No records of this group from the European Oligocene 
are available. The recent species of the subfamily are practically all 
forms belonging to cold, temperate regions, the few Oriental species of 
Stibadocera coming from mountains at considerable altitudes. 
The Tipulinae have been found as far back as the Mesozoic, but the 
records are not entirely satisfactory. In the lowermost Tertiaries, how- 
ever, undoubted tipuline forms occur. Species occur in the Green River 
shales of Colorado (Eocene). The group was well represented in the 
Oligocene (Baltic amber, Tulameen beds of British Columbia, Krottensee, 
and Gurnet Bay), and was very common in the Miocene (Radoboj, and 
especially in the Florissant of Colorado, where some twenty-five species 
of Tipula and closely ailied genera or subgenera have been described by 
Scudder and Cockerell). 
Tipulidae of the Pleistocene are not numerous, only a few having been 
made known from the refuse of lake dwellings in England (Dicaera, 
apparently related to Ctenophora), and in the African copal, including 
such genera as Styringomyia, Hlephantomyia, and Toxorhina. 
COMPARATIVE MORPHOLOGY 
The morphology of the various stages of crane-flies has been detailed 
elsewhere in this paper and need not be repeated here. 
PHYLOGENETIC CONSIDERATIONS 
The eucephalous familes of crane-flies are undoubtedly lower, phylo- 
genetically, than the Tipulidae, and the latter have been derived from 
the former. The generalized type recurs in all three subfamilies of the 
Tipulidae, and it:is uncertain which of these three should be. placed 
lowermost. Presumably all three groups arose from an immediate com- 
mon ancestor, or the Tipulinae and the Limnobiinae arose from one point of 
the tree, the Cylindrotominae developing from the limnobiine stem at a 
somewhat later period. The accompanying phylogenetic tree (Plate XII, 4) 
graphically illustrates this apparent evolution of the group. The Limno- 
biini show but little deviation from the fundamental type. From the 
level of the lowermost Hexatomini (Ula and Epiphragma), in close 
proximity to the Limnobiini, the remaining groups of crane-flies can be 
