Beetles 253 



grubs (Fig. 342) which lie in the mouth of a vertical burrow several inches 

 deep, with the dirt-colored head bent at right angles to the rest of the body 

 and making a neat plug for the top of the hole. When an unwary insect 

 conies in reach of this plug the waiting jaws make a quick grasp, and the 

 doomed prey is dragged down into the darkness. On the fifth segment 

 of the abdomen of the larva there is a hump, and on it are two small but 

 strong hooks curved forward. "This is an arrangement by which the little 

 rascal can hold back and keep from being jerked out of its hole when it gets 

 some large insect by the leg, and by which it can drag its struggling prey 

 down into its lair, where it may eat it at leisure. It is interesting to thrust 

 a straw down into one of these burrows, and then dig it out with a trowel. 

 The chances are that you will find the indignant inhabitant at the remote 

 end of the burrow chewing savagely at the end of the intruding straw." 



Plate III shows the appearance of the body and the character of the mark- 

 ings of the tiger-beetles, while the vivid color-effects are illustrated in Plate II. 

 In the East occurs, besides Cicindela, the genus Tetracha (PL III, Fig. i) 

 with two species; on the plains of the middle West the largest member of 

 the family, Amblychtla cylindrijormis , which hunts its prey at twilight, and 

 on the Pacific coast the genus Omus with ten species, all nocturnal. 



The family Carabidae, the predaceous ground-beetles, is a large one, 

 including in North America about 1200 species, representing over a hundred 

 genera. They are mostly dark-colored and are nocturnal in habit, hiding 

 by day under stones, chips, logs, etc., so not many of them are familiar or 

 even often seen. A few, however, are large and brilliantly colored, and 

 get discovered by most collectors. Like the tiger-beetles 

 they are active and predatory, with long strong mandibles 

 and slender running legs. They differ from the tiger -beetles 

 in their dislike of daylight, and in having the head in 

 most species narrower than the thorax. The larvae (Fig. 

 343) are "mostly long flattened grubs with a body of almost 

 equal breadth throughout. It is usually protected on top 

 by horny plates and ends in a pair of conical and bristly 

 appendages." Most of the larvae burrow just beneath the 

 surface of the earth, feeding on various insects which enter 

 the ground to pupate or for other reasons. They destroy 



large numbers of the destructive leaf-feeding beetles, whose ; I 4 ?' Larva 



of Calosoma sp. 

 soft-bodied larvae leave the plants and burrow into the (After Lugger; 



ground when ready to pupate. When full-grown the Carabid enlarged.) 

 larvae form small rough cells in the soil within which they change to pupae. 

 When the adult beetles emerge they push their way up to the surface. 



Plate IV illustrates several species of this family and shows the charac- 

 teristic flattened, usually rather broad although trim and compact, shape 



