INTRODUCTION. 
59 
appendage on each shoulder, havhig the appearance 
of a lappet ; these are niimed teguloe or base- covers, 
and are well exemplified in the genus Lithosia and 
its aifinities. This part of the body often hears one 
or more conspicuous dorsal tufts of feathery hair- 
like scales, of which the anterior and posterior are 
sometimes concave ; in which case the former has 
tJie concavity directed forwards, and the latter has 
it turned in an opposite direction. 
As appendages of the thorax, the legs next requhe 
a brief notice, hut they present nothing very peculiar 
in their formation. An exception to tins character, 
however, is perhaps to he found in the occasional 
great length of the coxae, which in the anterior legs 
of certain species ( Hypmia prohoscidalis, for ex- 
ample) are as long as the tibiae, and not much 
shorter than the thighs. The two last nat5ed 
divisions of the leg are often densely clothed irith 
long hairs, and the tihhe, in the fore pair, are usually 
furnished nith a strong spine on the inner side, 
which sometimes assumes the appearance of a rigid 
compressed lobe. In most cases this is the only 
projection on the anterior legs ; the mtermediate 
tibiaj generally have two spurs at the apex, and 
besides a similar pair in the hinder ones, there are 
often two others in the middle. The latter arrange- 
ment is frequently observed also in the intermediate 
tibiie. This portion of the leg often bears a pen- 
dant tuft of loose hair, which probably assists in 
balancing the body during flight ; and in some in- 
stances (as in the genus Aids ) the tibiaj have a 
