726 



CLASS IV. INSECTA 



in an articuated hook. The beetles of this family, known as the 

 Tiger-beetles, are active, predaceous Coleoptera feeding on small 

 insects which they run down. The larvae live in the ground, but, 



protruding their head, capture with light- 

 ning rapidity any insect which comes 

 within range. The family, which contains 

 some 1,400 species, is cosmopolitan but 

 mostly met with in the tropics. Cicindela, 

 the British tiger-beetle, has five species in 

 our country (Fig. 462). 



Fam. 5. Carabidae. Differ from the 

 preceding in that the clypeus is narrower 

 and the inner lobe of the maxilla has the 

 hook not articulated. Antennae pubescent. 

 Hind legs not markedly different from the 

 middle pair. The ground beetles comprise 

 about as many species as the Scardbaeidae. 

 The larvae are campodeiform and active, 

 with large nipper -like mandibles ; both they 

 and the images are as a rule carnivorous, 

 and devour insects, worms and snails. A 

 few have the wings rudimentary, and those 

 which dwell in caves are often blind, e.g. 

 Anophthalmus. Carabus, Bembidium, and 

 Harpalus are British genera. Pterostichu 

 (Fig. 378). 



Fam. 6. Amphizoidae. Antennae not 

 pubescent, outer lobe of maxilla without a 

 joint. Hind legs modified for swimming. 

 This family has but a single genus Amphizoa 

 found in both larval and imaginal stages in swift streams clinging to stones, 

 etc. 



Fam. 7. Pelobiidae. Antennae not pubescent, outer lobe of maxilla 

 jointed. Hind legs adapted for swimming. Tarsi longer than tibiae. 

 This family has also but one genus Pelobius found in Britain, South Europe, 

 Thibet and Australia. The larva has a superficial resemblance to a 

 gigantic zoea ; it breathes by branchial processes. The imago has power- 

 ful stridulating organs. 



Fam. 8. Haliplidae. Antennae ten-segmented, not pubescent, 

 Metasternum has a transverse suture. The coxae of hind legs form plates 

 which project under the abdomen and cover their femora. Small oval 

 aquatic beetles whose larvae bear a number of fleshy processes, which 

 may be respiratory as in Cnemidotus. There are but three genera, all 

 British, with a hundred species. Haliplus is cosmopolitan. 



Fam. 9. Dytiscidae. Antennae with eleven segments, not pubescent. 

 Hind legs capable of swimming only. Outer lobe of maxilla forms a two- 

 segmented palp. Metasternum has no transverse suture. A moderate 

 sized family of carnivorous water-beetles most abundant in the colder 

 regions. The larvae are active and ferocious creatures sucking up the 

 j uices of their prey through hollow mandibles. The images carry a supply 

 of air under the elytra. Many of the males have a peculiar pad or sucker 

 on their fore-feet, by which they adhere to the female. Dytiscus, Cybister, 

 Hydroporus, etc. 



FIG. 462. a Cicindela campes- 

 tris. b, c its larva with the two 

 dorsal hooks on the fifth 

 abdominal segment. 



