216 Transactions. 
the families of the Homoneura is as great as that between the suborders. 
n order to ascertain if any homologous structure was present in related 
orders, the Trichoptera and Mecoptera were examined. In the Trichoptera, 
species of the genera Rhyacophila, Psilochorema, Hydrobiosis, Hydropsyche, 
Polyplectropus, Triplectides, Notanatolica, Oecetis, Philanisus, Philorheithrus, 
а . 
Pycnocentria, Olinga, and Оесопеѕизѕ ; and, in t tera, Choristella. 
M 
certain that the tibial strigil in the Lepidoptera is peculiar to that order. 
The families of the Lepidoptera, as far as I have been able to examine 
them, will now be considered in order, and the modifications of the cleaning- 
apparatus described. 
Suborder HOMONEURA. 
MICROPTERYGIDAE. 
spur. Presumably, after development into a strigil, the structure moved 
basad or distad in sympathy with the tibial modification or other condi- 
middle of the tibia, and its apex rather less than a quarter from the tibial 
ex. Except for being somewhat swollen round the base of the strigil, 
the tibia itself is not modified ; there is not the flattening beneath, nor the 
formation of a groove, as occurs in the higher groups. 
MNESARCHAEIDAE. 
In Mnesarchaea the strigil is very much reduced, being only about four- 
fifths as long as the tibia is broad (fig. 4). It is clothed with scales similar 
to those on the tibia itself, and no hair is present. The reduction of the 
organ in this genus is apparently correlated with the type of antenna, this 
being filiform and scaled, with a few minute hairs. In Sabatinca the better- 
HEPIALIDAE. 
In the Hepialidae the strigil is not homologous with the structure so far 
described ; it 1s an outgrowth from the tibial wall instead of a modified 
spur. The Hepialidae are without tibial spurs, and it seems probable that 
but evolved a different organ to carry out the same function. At or near 
the base of and beneath the tibia there is a flap-like structure, covering 
the lower surface and extending usually about half-way along the segment 
(fig. 5). There is no indication of a hinge at the base, the strigil passing 
Р 
