336 



CHAPTER Y. 



SECTIONS HETEROMERA, TETRAMERA, AND TRIMERA. 



SECTION HETEROMERA : Beetles with Five-jointed Tarsi to the Four Anterior, and Four-jointed to the Two Posterior Legs- 

 Division of the Heteromera into Atrachelia and Trachelia Habits Churchyard Beetles Blister Beetles Hypermeta- 

 morphosis Singular Parasitic Habits and Mode of Development of Sitaris, Mcloe, Cantharis, Rhipiphorus, Hornia, 

 Bhipidius, and the Stylopidie SECTION TETRAMERA : Beetles with Four -jointed Tarsi Family CURCULIONID.E, or 

 Weevils -Family SCOLYTID<, or Bark Beetles Habits of some of the British Species Families BRENTHID.E, ANTHRI- 

 BIDJE, and BRUCHID.E (Seed-borers) Tribe LONGICORNIA Great Beauty and Variety of Form and Colours Night 

 flying and Day-flying Longicornia Musk Beetles Gigantic Species Mimetic Resemblances and Protective Disguises 

 Branch- sawyers Popular Errors on the Subject Tribe PHYTOPHAGA, or Leaf -eaters Strange Habits of some of 

 their Larvae Tribe EROTYLIDES SECTION TRIMERA : Beetles with Three-jointed Tarsi Lady -birds. 



SECTION HETEROMERA. 



THE Heteromera, Beetles with five tarsal joints to the first and second pairs of legs, and four joints to 

 the third pair, were divided by Westwood into two sub-sections, under the names of Atrachelia and 

 Trachelia, the former including a host of forms of prevailing dull black colours (though some genera 

 are metallic) and solid integuments, with the head sunk in the prothorax, the latter comprising all the 

 remaining families, and distinguished by the exserted head, softer integuments, and more varied 

 coloration. 



The ATRACHELIA form the single family TENEBRIOMD.E of recent entomologists, one of the 

 most numerous of the whole order, about 5,000 species having been described. Notwithstanding 

 their number, and the great diversity in subordinate points of their structure, they have all a com- 

 mon air of parentage, which renders their recognition easy, and the general similarity is extended even 

 to a peculiar and disagreeable odour which they emit. Nearly all are ground Beetles, inhabiting sandy 

 districts about the roots of herbage or under vegetable detritus, feeding on these or on animal sub- 

 stances, and being nocturnal in their habits. A few live under the bark of trees and in boleti. The 

 brighter metallic-coloured species live on trees, and are active by day. Some of the hard-bodied 

 genera are known for their extreme tenacity of life, the most interesting example of which is that of 

 a specimen of Zopherus breniei, an insect about an inch in length, and of stony hardness of 

 integument, which was exhibited alive by Mrs. Randolph Clay at a meeting of the Entomological 

 Society of London, about a year after she had received it from Mexico. It was carried on her 

 shoulder, secured by a gold chain round its waist, and had not tasted food since it had been in the 

 possessor's hands. The family are remarkable for the mimetic resemblances which many of their 

 species present : the form and garb of genera of other families, and particularly of the predaceous group 

 Carabidse, or of the lignivorous Longicornia, being most frequently assumed. The resemblance is so close 1 

 in some cases that it is only by counting the joints of the hind tarsi that the true nature of the insect 

 can be detected, without the dissection of the mouth. Preferring open, sandy districts, scantily or not 

 at all wooded, the family is most numerously represented and most varied in comparatively desert 

 regions, such as the borders of the African, Persian, and Central Asian deserts, the interior of North 

 America, and the drier parts of Chili. Among the few species found in the British Islands, the most 

 remarkable are Blaps mortisaga, or " Churchyard-beetle," Helops pallidus and striatus, and Opatruin, 

 subulosum, met with on sand-hills by the sea-shore. 



The Trachelia are less homogeneous than the Atrachelia, and have been divided consequently 

 into numerous families. The first of these, the CISTELID.E, are slender arboreal insects, with pecti- 

 nated tarsal claws. The NIHONID^E resemble certain convex Nitidulidae, and ai-e found in boleti in 

 tropical America. The MELANDRYID^: and PYTHID.E are composed of a small number of species, 

 inhabiting chiefly the north temperate zone of the New and Old World. Some of the latter, forming the 

 genus Salpingus, have the head prolonged into a snout, and bear some resemblance to Weevils. The 

 ANTHICIDJE are minute, agile Beetles, bearing a wonderful likeness to Ants ; many species are found in 

 Great Britain, chiefly running over vegetable debris in sandy situations. Next to these comes ;i 

 series of families allied to the Blister-beetle of commerce, some of the species of which are parasitic on 

 other insects in their early stages, and exhibit the extraordinary phenomenon called hypermetamorphosisi 

 that is, they undergo more than the normal number of changes ir. their growth from the newly- 

 hatched grub to the pupa stage. This abnormal metamorphosis is connected with or necessitated 

 by the peculiar conditions of their parasitic life, and presents features of great interest. 



