764 : CHARLES PauL ALEXANDER 
flies. That this resemblance is presumably not fundamental is suggested 
by the immature stages of these same generalized forms, which show 
but few features that can be reconciled with those of a panorpid-like 
ancestor. Unfortunately the fossil record helps but little. At the begin- 
ning of the Tertiaries, crane-flies were already numerous both in species 
and in individuals, but in most cases they are clearly referable to existing 
genera. It is evident, then, that the investigator must go still further 
back for his evidence, and the fossil crane-flies of the Upper Mesozoic 
are, unfortunately, still largely unavailable. The phylogenetic develop- 
ment of the group may be considered from two standpoints, the geological 
record and comparative morphology. 
THE GEOLOGICAL RECORD 
The most important works on fossil crane-flies are those of Loew 
(1850), Scudder (1894), Handlirsch (1906-08, and 1910, a and b), Meunier 
(1906), and Cockerell (1910, 1913, 1916, and 1917, a and b). The writer 
is indebted to Professor Cockerell for assistance in determining the age 
of many of the fossil-bearing beds. Excellent accounts of the various 
deposits may be found in Cockerell (1913) and in Tillyard (1917). 
The Tipuloidea, representing the superfamily of crane-flies, is herein 
considered as being constituted of six families, of which two, the 
Eoptychopteridae and the Architipulidae, did not survive the Mesozoic 
period. The Eoptychopteridae are known only from the Mecklenburg 
Lias (lowest Jurassic), and include but three monotypic genera. The 
Architipulidae are known from the same formation and include eight 
species arranged in three genera. The other four families contain recent 
forms and are included in this paper. 
The North American Eocene and Miocene, as represented by the White 
River and Green River beds and the Florissant shales, respectively, give 
evidence of having had a northern fauna, especially in the Eocene. This 
is well shown by the great development of the Cylindrotominae, which 
in the White River basin almost dominated the crane-fly fauna during 
the Eocene. It seems probable, moreover, that the group was forced 
into colder regions of the globe during the Oligocene, when the tropical 
element reached far to the north. No group of crane-flies that can be 
considered as being tropical has yet been found in the Florissant. On the 
other hand, the European Oligocene, as shown by the Gurnet Bay beds 
