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Have you ever watched a frog eating his dinner? The frog's tongue is attached near the front of his mouth. It is forked at the free end. When a fly comes within reach, the frog shoots out his tongue, curls the end of it over the fly, and drags his victim back into his mouth so quickly that it is hard to realize what has happened. Frogs eat a great many insect pests. They also eat worms and small fish. Certain larger fish eat frogs. Snakes and fish-eating birds such as cranes and herons will eat frogs whenever they can catch them.
Toads are very similar to frogs in appearance, but they usually have warty
skins. Most toads lay their eggs in strings of jelly rather than in masses. Like frogs, they develop from eggs into tadpoles and from tadpoles into adults. It is often difficult to tell them apart.
SALAMANDERS
Toads are not the only interesting relatives of frogs. Salamanders are members of the same large group of animals, called amphibians. All of them are cold-blooded, have bony skeletons, and usually live in the water for at least a part of their lives.
You may have noticed that the scientific names of animals are almost always taken from the Latin and Greek languages. This is true of plants, also, so that the names given are understood by all scientists, whether they live in different parts of the same country, or in different countries.
The animal kingdom is commonly divided into thirteen large groups, called subkingdoms, branches, or phyla. Each phylum contains animals having certain similar characteristics. The phylum Arthropoda is one with which those who have read this book are familiar, for it contains, among others, the classes Crustacea and Insecta, which are well represented in fresh water. The class Insecta includes the orders Diptera and Ephemerida which are also well known. The order Diptera contains, among other
families of two-winged flies, the family Syrphidae of which the drone fly is a member. The scientific name of the drone fly described in this book is Eristalis tenax. Eristalis is the name of the genus and tenax of the particular species of that genus to which it belongs.
Thus, you might say of the little drone fly which you can hold in the palm of your hand, "This one is of the kingdom Animalia, phylum Arthropoda, class Insecta, order Diptera, family Syrphidae, genus Eristalis, species tenax." However, you would call him Eristalis tenax, because his scientific name is made up of two names-those of the genus and species to which he belongs.
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