DEFENSE MECHANISMS OF ARTHROPODS. XL THE 
STRUCTURE, FUNCTION, AND PHENOLIC SECRE- 
TIONS OF THE GLANDS OF A CHORDEUMOID MILLI- 
PEDE AND A CARABID BEETLE. 1 
By T. Eisner, J. J. Hurst, and J. Meinwald 
Department of Entomology and Department of Chemistry, 
Cornell University, Ithaca, N. Y. 
In the course of exploratory field studies on arthropods with defen- 
sive glands, we came across two species which emit a strong and 
persistent phenolic odor when handled. One is a carabid beetle 
( Chlaenius cordicollis Kirby), the other a chordeumoid millipede 
[ Abacion magnum (Loomis)]. The fact that both animals produce 
repellent secretions is not surprising, since many other carabids and 
millipedes are well known for their defensive glands. But the particu- 
lar phenolic odor possessed by these two species is unlike the odor of 
any other arthropod secretion that has been studied (for a summary 
of defensive secretions of arthropods see Roth and Eisner, 1962). 
The purpose of this paper is to report on the nature of the two 
phenols involved, and to discuss the structure and mode of operation 
of the glands, as well as their defensive effectiveness. Both species 
were collected in the environs of Ithaca, N. Y. Abacion was from 
leaf litter in deciduous woods, and Chlaenius from beneath rocks near 
a creek bed. We had available for study ten specimens of Abacion 
and about two dozen Chlaenius. 
I. Glandular Apparatus and Discharge Mechanism, 
a. Chlaenius 
Chlaenius has a pair of glands, the openings of which are visible 
as two tiny slits, situated submarginally on the hypopygium a short 
distance behind the terminal spiracles (Plate 9, fig. 1). When a live 
This study was subsidized by Grant E-2908 of the U. S. Public Health 
Service and by a grant from Sigma Xi-RESA. We are indebted to Dr. P. J. 
Darlington, Jr., Museum of Comparative Zoology, Harvard University, and 
to our colleague Dr. W. T. Keeton, for identifying respectively the beetle 
and the millipede. The invaluable assistance of Mrs. R. Alsop is gratefully 
acknowledged. Thanks are also due to Dr. F. A. McKittrick for making the 
drawings, and to Yvonne, Vivian and Christina Eisner for collecting 
Chlaenius . 
Manuscript received by the editor November 19, 1962. 
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