THE CLASSIFICATION OF INSECTS 95 



the African tse-tse flies, of the genus Glossina, are also 

 included. 



The family Anthomyidce comprises a large number of 

 species which resemble small house-flies. Their larvae 

 usually feed upon decaying animal or vegetable sub- 

 stances, but some attack living plants. Among the latter 

 the cabbage root fly (Phorbia brassicce) is a well-known pest. 



The spider-flies (Hippoboscidce) include the wingless 

 " sheep-tick," or " ked " (Melopliagus ovmus), and the 

 forest-fly {Hippobosca equina). These insects and their 

 congeners are viviparous, and spend their lives on the 

 bodies of mammals or birds, whose blood they suck. The 

 allied Nycteribiidce live parasitically upon bats ; while 

 the family BrauUdie includes the minute, wingless insect 

 known as the bee-louse {Br aula cceca), which infests hive- 

 bees, being found most commonly upon the queen. 



Order XVIII. — Siphonaptera. 

 The fleas, which make up this order, are allied to the 

 Diptera, but differ from them in certain marked characters. 

 They are always wingless, while their bodies are flattened 

 laterally. The antenna? usually lie in little pits on either 

 side of the head ; the mouth-parts are modified for piercing 

 and sucking ; while the eyes are simple. The legs are long 

 and powerful, specially adapted for leaping. Adult fleas 

 are blood-sucking parasites, but the soft-skinned, active 

 larvae live in, and feed upon, dust. The pupa is enclosed 

 in a slight silken cocoon. There are two distinct families 

 of fleas : the Pulicidas and the Sarcopsyllidce. The former 

 are represented in all parts of the world, the largest species 

 being Hystric/iopsylla talpa?, which infests moles and field 

 mice. The latter — the so-called "jiggers" — are confined 

 to the tropics. After pairing, the females burrow into 

 the skin of small animals and man, giving rise to painful 



