THE LARGE SKIPPER 
381 
Anal Comb. In its last stages, the larva lives 
in a tubular dwelling comprised of several grass (i'll 
blades spun together ; it feeds on the portions \ , 
above its abode. On the under surface of the 1 V ' 
anal flap, directly above the anus, is a remark¬ 
able comb-like apparatus for the forcible eject¬ 
ment of its excrement. Just before the eject¬ 
ment of a pellet, the larva crawls backwards Lenticie of the 
until its extremity is either at or slightly pupa ' 
protruded beyond the tube; it then raises its anal segment, 
elevates the flap or lobe and evacuates the faeces, which 
remains adhering to the anus. The comb is then lowered 
to the rim of the orifice and remains fixed for a moment or 
two, apparently to obtain a firm pressure with the tips of the 
tines ; then, obviously with considerable power, it is suddenly 
released spring-like. The comb flies up with a violent jerk, 
casting the pellet with much force in an upward direction, 
when it falls to the ground at a distance of between 2 feet 
6 inches and 3 feet away. The comb is a semi-ovate chitinous 
structure consisting of eighteen asymmetrical tines, solidified 
over the greater portion, then separated and slightly turned 
outwards at the tips ; from the long central ones they gradually 
decrease in length ; the middle tine is dentated, the others 
have simple points. The colour is pale ochreous ; the four 
longest tines have black tips. 
Certain other lepidopterous larvae living in tubular dwellings 
are provided with somewhat similar anal combs for the pre¬ 
vention of fouling their abodes. Probably this remarkable 
organ reaches its highest perfection 
of development in the Hesperiidae. 
Pupa. The pupa measures 
19 mm. in length and is of a 
slender and almost cylindrical 
shape, but tapers to the anal seg¬ 
ment, which terminates in a com¬ 
pressed, flap-like projection and 
cremastral point with an ample 
cluster of amber-coloured hooks 
„ . . , . .. . ,.. , directed in various ways ; these 
Spiracle and lenticie of the larva . , , , . J 1 > ... 
Of the Large Skipper. are embedded in a mass of silk 
it 
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