2 Dr. & the Rev. S. Graham Brade-Birks— 
have been recorded as luminous we are not now concerned, 
aud pauropods aud symphyles are not known to produce 
light. Among the centipedes, which have some affinities 
with insects, only one great group—the Geophilomorpha— 
is known to exhibit the,phenomenon with which the present 
study deals. 
The elongate body of a Geop! tilomorph (fig. 1) consists 
of a head anda large number of sulbsimilar segments, each 
but the last of which bears a pair of walking legs, Each 
leg-bearing segment is more or less flattened dorsally, 
ventrally, and laterally, the dorsal and ventral surfaces 
+ 
Bio, Ae 
cl eae 
ol sy ante a 
‘i 
Geophilus carpophagus, Leach, g, X 5:0, collected at Darwen, 
Lancashire, July 1919, H. K. B.-B. ad nat. del. 
being subequal and wider than the lateral surfaces. The 
legs arise from the external margins of the ventral surface, 
and the stigmata, or breathing-pores, are found on the 
lateral surfaces. The integument of each segment is 
supported by aseries of chitinous plates, some of which have 
been used by M. Henry W. Brélemann (3), the eminent 
French myriapodologist, for purposes of classification. 
Characteristically the ventral surface possesses one median 
unpaired plate (the sternite), and the dorsal surface has 
two unpaired plates (a posterior tergite and an anterior pre- 
tergitc). In front of the sternite is a pair of plates (the 
presternal plates), which in certain cases meet and fuse in 
