BY C. J. GAHAN. 
65 
spiracles on the metasternum—one on each side of it near 
where it joins the mesosternum—spiracles as large as 
any of the others which are present. Some Lycid and 
Lampyrid larvae have spiracles in a similar position, but 
very much reduced in size compared with the others, and 
probably altogether functionless in character. 
Why the metathoracic spiracles should be so well deve¬ 
loped in these “ trilobite ” larvae is not quite clear. Their 
absence, or rudimentary condition, in other beetle larvae is 
sometimes explained as being due to the need of room for 
the development of the wing muscles, and, if that be so, 
their presence would suggest that the larvae possessing 
them never develop into winged insects. But, so far as I 
know, they are present in all of these peculiar larvae. Are 
these larvae, then, all of one sex, or is it possible that 
the larvae of the males may be quite unlike those of the 
females ? 
Thus it will be seen that there are several questions of 
interest waiting to be settled by anyone who may succeed 
in tracing out the full life-history of those still problematic 
larvae. 
For the convenience of those readers of this Journal 
who may take a lively interest in the subject, I append a 
short list of books and papers in which reference is made 
to it:— 
1. Perty, ‘ Observationes Nonnullae in Coleoptera Indiae 
Orientalis,’ 1881, p. 88, pi. i. figs. 8 and 9. 
2. Westwood, ‘ Introduction to the Modern Classification 
of Insects,’ 1889, vol. i. pp. 254, 255, fig. 27, 1, and 
fig. 28, 1. 
8. Erichson, in Wiegman’s ‘ Archiv fur Naturgeschichte, 5 
1841, i. p. 91. 
4. Candeze, * Histoire des Metamorphoses de quelques 
Coleopteres Exotiques,’ 1861, pp. 29-34, pi. iii. 
fig. 1. 
5. Kolbe, 1 2 * 4 5 6 7 8 9 Entomologische Nachrichten,’ vol. xiii. 1887, 
p. 37. 
6. Gahan, * Natural Science,’ vol. xii., 1898, p. 43, 
fig. 2. 
7. Sharp, ‘ Cambridge Natural History,’ Insects, part ii. 
1899, p. 251. 
8. Bourgeois, * Bull. Soc. Entom. de France,’ 1899, 
pp. 58-63, figs. 1 and 2. 
9. Gahan, * Proc. Ent. Soc. London,’ 1908, p. xlviii. 
F 
