THE CHEMICAL NATURE OF SOME INSECT SECRETIONS. 
BY A. L. ME LANDER AND C. T. BBUES. 
In this paper we have attempted to give in addition to some 
original observations, a brief resume of what is definitely known 
regarding the general chemistry of the odors of insects and 
myriapods. 
Most of the odorous secretions of insects are the products of 
highly specialized glands which derive from the blood the founda- 
tion for their work. An exception to this, however, is seen in the 
fat occurring associated with the chitinous skeleton of insects. 
Of the glandular secretions one may define two categories: those 
used by the insect directly in its own metabolism, and those of 
more indirect use as an odorous character and developed to suit 
peculiar conditions of environment or habits. As the first group 
includes products found elsewhere throughout the animal 
kingdom, e. g., the salivary, digestive, and excretory fluids, all 
secreted by portions of the alimentary tract, we shall pass them 
by to consider those substances more or less peculiar to insects 
themselves. These products are of two kinds; defensive, malo- 
dorous, highly volatile liquids developed principally to repel 
predaceous enemies ; and alluring, sweet-scented or sweet-tasting 
fluids used to attract the two sexes of a species or the individuals 
of a community, or even to insure protection by other species as 
is the case with many myrmecophilous insects. 
We are not aware that anyone has ever attempted to classify 
insect odors, but Kerner and Oliver ('95) p. 199, have divided the 
odors of flowers into the following groups: indoloid, aminoid, 
parafifinoid, benzoloid and terpenoid. As other scents seem to be 
developed in insects and some to be lacking, this classification is 
not wholly suited to our purpose. Accordingly, we have used the 
following outline in the absence of a more satisfactory one. It 
includes six rather heterogeneous groups: Ethereal and Ben- 
zoloid, Indoloid, Isonitrile, Vegetable extracts, Acid, Alkaline. 
ETHEREAL AND BENZOLOID. 
The European bugs of the genus Pyrrhocoris secrete a sweet 
smelling and pleasant tasting etheral liquid, according to Mayer 
('74). The Texan ant, Camponotus maciilatas sansabeanus, has 
a marked scent resembling a combination of butyric and valer- 
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