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mately twenty-two months old, it chooses a suitabie spot on the surface of 
the ground and builds a lattice work of soft earth over itself in the shape of 
a small dome, by which means it conceals itself in about a day. In the con- 
struction of this cell the larva removes earth from underneath itself by 
means of its mandibles. This it masticates in its mouth for a short time, 
after which it regurgitates it in the form of a short ribbon-like mass, 
which it applies to the walls of the chamber. 
Almost as soon as this chamber is completed the larva becomes sluggish 
and transforms to a pupa. The extent of the pupal period was found to vary 
from sixteen to eighteen days, at the end of which time the pupae trans- 
formed to adults and emerged. 
So far as the economic importance of fireflies is concerned it is generally 
believed that they are of little or no importance. This conception is far 
from correct. It is true that the adults are of little value as most of them 
probably eat comparatively little, and most of the insects upon which they 
feed are not injurious. The larvae, on the other hand, are voracious little 
creatures which feed largely upon injurious species of animals, such as 
cutworm larvae, slugs, snails, etc. Most of the soft bodied animals liv- 
ing on the ground are injurious (unless it is the earthworm), and as the 
food of firefly larvae is probably limited to these small animals, they nee- 
essarily do much economic good in killing them. The slugs and cutworm 
larvae are among our worst economic pests, and it seems evident that they 
furnish a large part of the food of these larvae. Most of our fireflies live 
two years as larvae, hence the number of larvae that are feeding on the 
ground during any season is approximately twice that of the adult fireflies. 
Any one who has been out during a June or July evening, knows that the 
fireflies are one of our most abundant insects, which together with the vorac- 
ious habits of the larvae leads one to the belief that they are of much 
more economic importance than has been attributed to them heretofore. 
