96 BRITISH LEPIDOPTERA. 



accelerated, until, in the larva of Macrurocampa, it culminated in a 

 pair of anal filaments, with their evertible flagella as fully finished as 

 in Centra, the larva using these in the same manner as deterrent 

 structures (Bombycine Moths, etc., p. 31). 



The larva of Pirachola isocrates, the well-known Pomegranate 

 butterfly, is said by Pargiter to have two white spots near the anal 

 end, in each of which is a small horn-like process, which the larva 

 continually protrudes and retracts. This observer, however, confused 

 these eversible structures with the honey-gland on the dorsum of the 

 7th abdominal segment of certain species, and which is so attrac- 

 tive to ants. Niceville gives (Butts, of India, vol. iii.) an excellent 

 account of two tubercles with protruding flagella, found one on each 

 side of the 8th abdominal segment of Curette thetis. These are 

 described as two diverging, cylindrical, rigid pillars, arising from the 

 sub-dorsal region, and of a pale green colour. When the insect is 

 touched or alarmed, a deep maroon tentacle, as long as the rigid pillar, 

 bearing on its end long particoloured hairs (the basal third black, and 

 upper two-thirds white) is everted. The maroon tentacle, with its 

 long hairs spread out like a circular fan or rosette, is whirled round 

 with great rapidity in a plane parallel to its body, its use being, almost 

 certainly, to frighten away its enemies. Similar eversible glands are 

 described by Hagen as occurring in the larvae of Plebeius argus and 

 Polyommatus corydon. He writes : " You find on the penultimate seg- 

 ment, outside and behind the stigmata, two large white spots, each of 

 which evaginates a white membranous tuBe, just like the finger of a 

 glove, the tip of which is not entirely drawn out." Exactly what 

 measure of protection is afforded by these flagella is not known. They 

 are by no means generally present among Lycaenid larvae, closely 

 allied species often differing in this respect. Many authors (including 

 Dimmock and Scudder) incline to the opinion that they are of the 

 nature of osmateria, and diffuse odours, but the supposition is alto- 

 gether without support, so far, that at present, no such odours have 

 been detected. 



On the dorsum of the 6th and 7th abdominal segments of many 

 Liparid larvss, are to be found (after the first moult) a pair of ever- 

 sible glands. In the larvre of Dasychira pudibunda and D. fascelina, 

 however, only one gland is present, viz., that situated in the medio- 

 dorsal line of the 7th abdominal segment, which becomes everted 

 when the larva rolls up on being disturbed. Poulton states that the 

 larval surface, close to the lips of the aperture, seems to be extremely 

 sensitive to tactile impressions. He also describes (Trans. Ent. 

 Soc. Lond., 1886) two medio-dorsal, orange-coloured glands situated 

 towards the anterior margins of the 6th and 7th abdominal segments 

 in Porthesia similis (auriftua) capable of secreting a pale transparent 

 fluid, which Swinton believed was poisonous, but which Poulton finds 

 to be odoriferous. Bacot says that the eversible glands are very 

 active in the larva of this species, and are far more frequently 

 seen in operation than in other Liparid larvre. All the British 

 species of the Liparids appear to possess these glands except Demas, 

 although, as we have seen, Dasychira only possesses one of them. 

 Bacot points out that, in addition to these, the larvae of Psilura 

 vwnacha and Porthetria dtepar have a small yellow gland on the first 

 four abdominal segments, placed one on each side of the medio-dorsal 



