FOSSIL BEETLES. 299 



sensitive surfaces of the thin plates forming the apical joints of the antennae of the true Lamellicornia 

 are shown to be of high importance to the economy of the insects, by the care Nature has taken in 

 protecting them. Pits, crowded with sensitive pores, exist very generally throughout the great family 

 Buprestidae. In Longicorns, where the stridulating organs are so well developed, and the sense of 

 hearing ought to be acute in correspondence, the antennae are often beautifully sculptured with parallel 

 .striae, but this is chiefly in the male sex, and it is b3lieved that it is the length rather than the texture 

 of the antennae which in this family adapts them as effective organs of hearing. The Adephagous, or 

 carnivorous families, present a minute porosity and fine pubescence on most of the antennal joints, 

 leaving always a small number of smooth basal ones, the number of smooth joints being of 

 remarkable uniformity in each sub-family or group of sub-families. 



A very large proportion of the species of Coleoptera, especially in hot countries, come forth from 

 their hidden feeding-places only after sunset, and a large number pass their whole lives in concealment. 

 Owing to this circumstance, it is only a small minority of the Beetle fauna of any district which meets 

 the eye of the inexperienced naturalist in his mid-day rambles throughout the summer months. This 

 minority consists of such diurnal species as are found on foliage and flowers, or running about over 

 banks and pathways, or on the wing ; such species are most abundant in the spring or early summer, 

 the first heats of July sending back to their hiding-places all except those which have by that time 

 provided for the continuance of their species and died. But the bulk of the species are never seen in 

 the open in broad daylight ; they have to be sought for in their hidden haunts, amongst vegetable 

 debris and garbage of all descriptions, about the roots of herbage, under stones, in and under bark, and 

 in decaying timber, in water rich in aquatic vegetation, in ants' and wasps' nests, in the soil by 

 digging, in the interior of stems of plants, in moss, in manure heaps, under boulders, in the recesses 

 of caverns, and in many other situations where it would seem but little likely they should occur. In 

 tropical countries a large number of species are never seen except on the rare occasions when they fly 

 abroad in sultry evenings at the beginning of the rainy season, at which time they may be attracted by 

 a light placed in front of a sheet or a whitewashed wall. Sometimes their flight is continued far into 

 the night, and if a sudden shower occurs, chilling the air, whilst they are traversing a river or 

 lake, they are cast down by myriads into the water, their half-drowned bodies being cast up by ripples 

 on to the beaches, where a fine harvest of rare species, never otherwise seen, may be gathered by 

 the collector. A similar phenomenon occurs also when sudden floods inundate a river valley, in 

 temperate as well as hot countries. If this happens in the spring, and in a district generally favour- 

 able to insect life, the waters sweep down nearly the whole Beetle population from the upper valleys 

 to the lower plains, where, amongst the trees and bushes, every stem and leaf may be seen 

 covered with a miscellaneous crowd, endeavouring to escape from the deluge. The floating debris on 

 the water will also swarm with other half-drowned crowds, and when the flood subsides, a little 

 industrious collecting from the sediment stranded on banks, or deposited in trees and hedges, will yield 

 a larger number of species than could be found by ordinary search during a whole summer in the 

 same district. 



Before concluding these introductory remarks on the order, a few words may be said regarding 

 fossil Coleoptera. When the highly-specialised structure of Beetles and the absence in the existing 

 creation of connecting links between them and other orders of insects are considered, both of 

 which require long periods of time to bring about, it is not a matter of surprise to find that the 

 type is of great geological antiqxiity. As far as our present knowledge goes, however, Beetles 

 were preceded in time by the more lowly-organised orders Neuroptera and Orthoptera. The 

 earliest insects known have been found in rocks of the Devonian period in North America, and 

 belong to the Neuroptera. Coleoptera first make their appearance in the subsequent Carboniferous 

 Age ; but they seem to be of very rare occurrence, as only two species have been detected, one 

 a Weevil (Curcidioides cmsticii), and the other a Lamellicorn, resembling the existing genus Trox, 

 and named Troxites germari. That these earliest of all known forms should belong to two of the 

 most highly organised families of the order is a matter for legitimate surprise ; and the fact is only 

 to be explained on the hypothesis, in which all modern biologists are agreed, that our oldest 

 fossiliferous strata are far more recent in date than the origin of life, or even the commencement of 

 differentiation of the oixlers in the lower classes of the animal kingdom. Later on, in the Secondary 



