THE BEETLE, 57 



(4) On the side of the abdomen now exposed look for 

 lines of separation into segments. How many segments 

 are there? Near the outer margin between the segments 

 find the spiracles. Look at them closely and make out their 

 shape and structure. Draw dorsal view of the animal as 

 now exposed (X2). 



Development.; — The eggs of the Harpalus are laid in 

 protected places under boards and the larva, like the imago, 

 is carnivorous. It has strong jaws and three pairs of jointed 

 legs and is called a grub. From the larva it passes into 

 the pupa state, from which it afterwardS' emerges an adult 

 beetle. 



Habits. — From the structure of this animal's mouth parts, 

 what kind of food would it relish ? Where is it found most 

 abundantly? Is it beneficial or injurious? Study the living 

 specimen. Note its excited motions in captivity. Can you 

 tell why? Estimate its strength by tying it by the third 

 leg to test its power of pulling, and also by putting a 

 weight on its back. 



Classification. — The Harpalus caliginosus belongs to the 

 order Coleoptera and to the family Carabidae. The family 

 contains many common beetles, some of which you have 

 probably collected already. What other families of beetles 

 have you represented in your collection ? What is the mean- 

 ing of the term coleoptera? How does it apply to this 

 order ? 



Watch the Harpalus under the electric lights to find its 

 habits of food getting. Does it fly? Try to make one fly 

 Some beetles of this family have no inner wings, and the 

 outer ones have grown together. Can you tell why ? Could 

 their habits produce this effect ? 



