REPORT OF THE STATE ENTOMOLOGIST I9Q07 219 
It may be observed in any wing that costa, subcosta and radius 
run closely parallel along the front margin of the wing and that 
the subcosta lies in a deep groove between the other two, and is 
usually strongly braced against them. Thus, both by approximation 
of these strong veins and by the corrugation of the membrane, the 
front of the wing is made rigid. The other posterior veins extend 
wide apart diagonally across the outspread membrane of the wing 
disk. 
The cross veins of a crane fly wing are rarely more numerous, 
usually less numerous than are the longitudinal veins. A humeral 
cross vein (/) strongly joins the costal and subcostal veins near 
the base. The other cross veins of the wing that are considered 
typical for the Tipulidae lie in the distal part of the wing and may 
be conveniently designated by the names suggested by their posi- 
tions, as follows: the radial cross vein (7), the radio-medial cross 
vein (r-m), the median cross vein (m), and the medio-cubital 
cross vein (m-cw), small letters being used as symbols to avoid 
confusion. 
This system of venation is characteristic not only of all Tipulidae, 
but also of all Diptera, and of a number of other orders of insects 
as well. In so far as the trunks of the principal veins are con- 
cerned, it is characteristic of all winged insects. 
Toward the working out of the system of the venation of the 
Diptera, systematic dipterologists have contributed surprisingly 
little, and toward the correlation of it with that of other orders, 
they have done nothing at all. Redtenbacher laid the foundations, 
and Comstock built thereon, and by comparative study established 
the system on a firm basis and published it in his Manual for the 
Study of Insects. He once told me that it was in the study of the 
venation of the Diptera that he first felt the solid ground of true 
homologies beneath his feet. I have had hitherto no share in the 
brilliant work that has been done on the venation of this order. 
The chapters on Diptera, Hymenoptera and Lepidoptera of the 
Wings of Insects were wholly the work of Professor Comstock. 
‘ After this work was done I joined him in a search for ontogenetic 
confirmation of homologies already determined; but in the order 
Diptera, that search proved wholly fruitless. The proof of homo- 
logies in dipterous venation rests on comparative anatomy alone. 
When Professor Comstock and I published jointly the Wings 
of Insects, we endeavored to construct a wing that should be typical 
for all the orders. Afterward, studying ‘the venation of the 
