1967] 
Eisner j Alsop & Eisner — Defense Mechanisms 
109 
a 
b 
Text-fig. 2. Top, diagram of Apheloria, showing the gland openings 
(white spots) on the notal margins. Glands on segments 9 and 10 have 
discharged their secretion. The cutaway showing the gland in segment 5 
is enlarged below. The reservoir of the gland (a) contains emulsified 
mandelonitrile. A valve operated by a muscle separates the reservoir 
from the smaller vestibule (b), which contains the catalyst. 
Cyanogenesis in millipedes has never before been measured. How- 
ever, naturalists have long been aware of the considerable potency of 
the secretion, and it had been noted that a container with cyano- 
genetic millipedes could serve as an effective “killing jar” in which 
insects and other small animals would not long survive (T. Eisner 
and H. E. Eisner, 1965). We have found the vapors liberated by 
freshly disturbed Apheloria to be rapidly fatal to houseflies confined 
with the millipede in a small vial, and others have made comparable 
observations (Davenport et al., 1952). 
MATERIALS AND METHODS 
The millipedes 
Apheloria and Pseudopoly desmus were taken at Ithaca, N.Y., in 
an area of about an acre on a woody hillside beside a brook, in moist 
leaf litter and under rocks. They were collected at various dates 
throughout their active season, from early May to late November. 
They were assayed for hydrogen cyanide production within less than 
four days after capture. 
