602 EXTERNAL ANATOMY OF INSECTS. 
are commonly of a more dark and dismal aspect and 
colour than those which feed upon such as are living 
and fresh, denominated thalerophagous by the same 
learned author; this you may see exemplified in his 
Scarabeide and Cetoniade. Again, in the Predaceous 
beetles a similar contrast of colours is often observable. 
How brilliant and gay are the fierce Cicindele! those 
tigers of insects, as Linné calls them; how black as to 
colour, how horrible in aspect is their near relation the 
Manticora: what difference exists in the economy of 
these animals is not known, except, as I learn from Mr. . 
Burchell, that the latter is subterraneous, whereas the 
former seek the sunbeam and fly rapidly. I shall now 
point out a few instances in which the colours of their 
elytra distinguish tribes or families. Amongst the Pre- 
daceous beetles a large family of the Cicindelide are 
distinguished by a middle angular white band, and se- 
veral white dots on their green or brown elytra, as in 
C. sylvatica ; a family of Brachinus, and the majority of 
Mylabris, Lamia capensis and fasciata, &e., by black 
elytra, with yellow or red bands; Carabus violaceus and 
affinities by the violet margin of these organs; Callio- 
chroma and Cerambyx by their sericeous, and Eumolpus 
by their metallic, lustre. These instances will be suffi- 
cient to turn your attention to this subject, which though 
not of primary importance in discriminating genera, Xc. 
is not without its use in a secondary view. 
10. Uses. I must not quit this subject without saying 
something upon the ends which elytra seem designed to 
serve. ‘Their first and most obvious use is the protec- 
tion of the wings when unemployed, that they may not 
be lJacerated or soiled, and rendered unfit for flight in 
