COLEOPTERA 361 



of the spider is spun by a special organ at the end of the body, 

 that of a caterpillar proceeds from the mouth. By this thread 

 the caterpillar suspends itself from its food-plant, or lowers itself 

 to the ground, and the thread also provides material for those 

 loopers that make a cocoon. This silk hardens upon coming in 

 contact with the air, just like that of the spiders. 



COLEOPTERA 



The great order COLEOPTERA, that is, the "sheath-winged" 

 insects, is well defined from almost all other insects by its charac- 

 teristic marks. The members of this group undergo a complete 

 metamorphosis, like the Diptera and the Lepidoptera, from grub 

 to pupa, and from pupa to the perfect insect. But they are easily 

 distinguished from these by the fact that their "fore" or upper 

 wings are modified into wing-cases, or "sheaths", as their general 

 name implies. 



These sheaths are hard or horny, and are styled elytra; while 

 the inferior or under wings are their true wings, and their only 

 means of flight. As a rule these insects fly well, the wing-cases 

 being held up while the two wings are in use. When they alight 

 they fold their wings, and tuck them away under their protecting 

 "sheaths". 



We have only to mention the name " beetles " to realize what 

 our Coleoptera are like. We know them already when we see 

 them, and we know that many of them are magnificently coloured. 

 And when we speak of tiger-beetles, stag-beetles, water-beetles, 

 weevils, musk-beetles, and the beautiful little lady-birds we begin 

 to feel at home with them. 



This is a very great group as to families, and genera, and 

 species — the lady-birds alone number about a thousand species — • 

 but none of them can be said to be very large. Some foreign 

 species that reach the size of the palm of a large hand are con- 

 sidered to be gigantic. On the other hand, many of the beetles 

 are exceedingly small. 



