THE CADELLE 23 
of them died after living a few months, none completed their de- 
velopment, and the few that were still alive after 18 months were 
only about half grown. Certain larvae lived to be about 2 years old 
without reaching maturity. 3 
Larva often found iri substances upon which it does not feed. — 
When well grown the larva may migrate from its food in search of 
a protected place in which to form its pupal chamber and transform 
to the adult stage. The larva may therefore be found in strange 
places and foods and cause unnecessary alarm. Thus larvae may bore 
into bags of sugar (30) and salt, cornstarch, rolls of carpets and 
rugs, balls of twine, corrugated cardboard, in soft wood, and have 
even been found in bottles of milk (%8). Of course their presence 
in such places is accidental and usually is of no economic importance 
except as they render such foods unpalatable if their presence is 
noted. In certain instances the cutting of fibers, etc., by the larvae 
in forming their cocoons may seriously affect a commodity. 
CARNIVOROUSNESS OF LARVA 
Much has been said regarding the carnivorous habits of the cadelle 
larva, and a survey of the literature relating to this insect would lead 
one to suspect that the larva kills and devours any other insect larva 
that it chances to encounter. To determine the truth of the matter 
a large number of cadelle larvae were confined separately in small 
glass vials with a small quantity of flour and a number of larvae of 
other flour-infesting insects. At the end of a few weeks the vials 
were inspected and it was discovered that in almost every case all 
the larvae were alive and thriving although the cardelle larva must 
have been in a more or less close contact with some of the other larvae 
most of the time. In a few cases some of the other larvae were found 
dead and these probably had been killed by the cadelle larva. 
Further experiments were conducted by placing several cadelle 
larvae together in glass Petri dishes with and without food and 
with or without other insect larvae. It was found that the cadelle 
larvae upon encountering each other would frequently thrash around 
and inflict wounds with their mandibles which in time caused death 
to ensue. In this way in the course of a week or two a good many 
were killed, but the living larvae made no attempt to feed upon the 
dead bodies, and it seems quite likely that the mortality was due 
mainly to the restricted space rather than to any carnivorous pro- 
clivities of the larvae. The other insect larvae that were confined with 
the cadelle larvae fared much better than the cadelles, possibly because 
of their smaller size and greater activity ; a few were killed but the 
majority escaped and there was no evidence to show that the cadelle 
larvae fed upon the remains! of the few that were killed. In one 
instance a cadelle larva was accidently confined in a vial with the 
larva of the black carpet beetle (Attagenus piceus Oliv.) for several 
months without food. Upon examination both larvae were found to 
be alive and uninjured. 
LENGTH OF LARVAL STAGE 
The length of the larval stage varies considerably. It is influenced 
by various factors, the more important of which are the abundance 
3 This is true in spite of the fact that tremendous numbers of well grown larvae have 
been taken from white flour that has been in storage for some months. 
