THE CRANE-FuIES oF New YorK— Part I 843 
REARING THE IMMATURE STAGES 
As has been stated elsewhere, the author believes the most important 
work yet to be done in entomology is the study of the immature stages 
of the various groups of insects. In most cases it is necessary to rear 
the immature stages thru to the adult in order to be certain of the species, 
and this process of bringing the larva to the perfect condition is often 
attended with many difficulties. The author has spent several years 
in rearing the local Tipulidae, and a general statement of the methods 
adopted is here given. 
It should be borne in mind that the bringing of the larvae from their 
natural habitat into the warmth of the laboratory accelerates their develop- 
ment, and the adults emerge in the breeding cages a week or two earlier 
than in nature. 
Aquatic forms 
The aquatic forms are among the most difficult to rear, especially 
the species living in rapid, well-aérated water. It must be understood 
at the start that practically all crane-flies require earth, sand, or a similar 
solid material in which to pupate, and it is often very difficult to provide 
rushing torrents for the larval life together with solid earth for the pupal 
existence. Breeding cages, consisting of wire cylinders the ends of 
which are covered with cheesecloth, have been used with considerable 
success. The mesh must be of sufficient fineness to retain the larvae 
inside, but not so small as to exclude the food that is carried in the current; 
however, since this food is microscopic or very small, a fine mesh is suffi- 
cient to allow its entry into the cage. The whole cage can be transferred 
to the natural haunt of the larva and kept under observation until the adult 
insect emerges. The main difficulties with this method are the danger of 
smothering the insect by deposition of silt during high water, the washing 
away of the entire outfit during storms, and the inconvenience, in most 
cases, of having to make many long trips to the scene of rearing before 
the final result is obtained. In almost all cases when the species could 
be reared by the use of such breeding cages, the writer has been able 
to get adult flies by placing the full-grown larvae in medium-sized (four- 
ounce) shell vials together with some earth from their natural habitat. 
In order to prevent evaporation, small caps of cheesecloth may be fas- 
