female exists in the male. The male is not known to be luminescent (Pl. 27, Fig. 11.). (5) The larva is oblivious to various types of noises, and is not alarmed until its snare is touched, when it retreats within two or three seconds, usually backwards, into a prepared hiding place, which action quickly covers its light. (6) Larvae at night can be dislodged by a quick thrust of a knife, fall down the bank, and continue lighted up. They may, but generally do not, douse their light under these circumstances, for some hours, and can be found lighted up wandering on leaves on the same and on the following evening. Larvae tend to douse their light shortly when a flash-lamp is turned on to them. (7) Of a number of larvae placed on moss in a box, some continue luminescent, some douse. The larva has the power slowly to fade out its light in about a minute. (8) No imaginal discs develop in connection with the light organs, but the larva clears out the pink excretion granules in its malpighian tubes before pupation. (Pl. 24, Fig. 6.) (9) In direct light the full grown larva (Pl. 23, Fig. 4) is brownish black in front, brown further down, pink in the mid lower region, and mainly hyaline towards its posterior end. Larvae about to metamorphose have lost their pink colour through evacuation of excretion granules. (10) Silk and mucous glands of the larva are separate and large (Pl. 24, Fig. 5). The mucous glands are chocolate brown in colour. The mucus droplets are not coloured. (11) The nervous system of the larva is not known to be peculiar in any way. The ganglia are large, and the last segment is served by a ganglion lying in the segment in front (Pl. 25, Fig. 7A). (12) There are larval integumental scolophore tactile sense organs (Pl. 26, Fig. 8) in the two terminal anal papillae. Two of the four scolopale organs are provided with an external seta, one curved, one shorter and straight. Two others have no setae. A nerve from these sense organs passes to the ganglion in the segment in front. (13) The head has a dorsal pair of aggregate eyes with a single facet, and a more ventral sense organ of the lateral ocellus type. The antenna is reduced to a drum-like base. The jaws are powerful and sharply toothed; below are powerful maxillae, also serrated, but not so sharply. In between is an eversile basket-like bristled sac which may be an epipharynx (Pl. 25, Fig. 7B). (14) The brain lies almost completely behind the head. The innervation of the reflector and light organs is not understood. (15) The light organs of the larva (Pl. 27, Fig. 12), as in the adult insect, are the swollen distal ends of the four malpighian tubules. These latter are divided into four regions; where they originate from the posterior end of the mesenteron the tubes are free of excretion granules, then there is a large, much longer, wider pink region of granules, then a tapered region with fewer granules, which is bound to the intestine, then a short similar area free of granules, then finally the light organs. There appears to be a close physical, but no tracheal connection between the boat-shaped reflector and the light organs (Pl. 24, Fig. 5). The whole segment containing the light organs and reflector can be telescoped within the segment in front by the contraction of longitudinal muscles (Pl. 25, Fig. 7). (16) Optical microscopy shows that the light organ cells have increased numbers of mitochondria. (17) Control of luminescence is not properly understood. When the last segment containing the light organ is cut off, the light continues for as long as two