DIPTERA 543 



[This beetle is common in many parts of the world amongst 

 groceries, corn, meal, seeds, dried fruits, etc. It is about -f^ in. long, 

 much flattened and chocolate-brown in colour. The thorax has two 

 shallow grooves and bears six minute teeth on each side. The jaws 

 are strong, but the bite cannot be very serious. F. V. T.] 



Order. Diptera or Siphonaptera. 

 Aphaniptera (Fleas). 



Wingless, the thoracic rings distinct and free ; antennae of three segments ; legs 

 very powerful ; abdomen with nine segments. [Ten segments are present, but only 

 nine are visible. F. V. T.] The mandibles transformed into serrated puncturing 

 organs, which are situated in the split sheath of the rostrum ; the maxillae are 

 laminated and have palpi, and more or less conceal the other parts. 



The importance of fleas lies mainly in the fact that they act as plague carriers. 

 About 150 species have already been described. The only ones of importance for 

 this work are those found on man and those on rats and mice. The two families 

 in which these are found are known as Pulicidce and Sarcopsyllidce. 



The eggs of fleas are laid on the ground, on nigs, etc., and in birds* and rodents' 

 nests. They hatch rapidly in warm weather and in warm climates, varying from 

 two to five days ; in cold countries they may take two or three weeks to incubate. 



The larva is a footless creature, pearly white in colour, the head sometimes 

 being darkened, composed of fourteen segments including the head, and although 

 apodal can move with considerable agility. It lives amongst dust and dirt, and 

 feeds upon any organic matter it can find. In about two weeks it is said to become 

 mature, and then spins a cocoon in which pupation takes place. 



The cocoons of the common human flea and the fowl flea become covered with 

 dust and dirt. The period of pupal life seems varied, for I have had the fowl flea 

 hatch out in ten days, and others in three weeks at the same time of year. 



The adults are a blood suckers and cause considerable irritation as well as 

 acting as disease carriers, and in the Sarcopsyltida the females attach themselves 

 permanently to their hosts, embedding themselves under the skin, where they 

 become pregnant. Some kinds harbour the cystic stage of tapeworms, and the rat 

 trypanosome passes certain stages in the rat flea. Most fleas have definite hosts, 

 but some, like the rat and fowl fleas, attack man. 



The fleas which can carry the bacillus of plague are Xenopsylla cheopis, Pulex 

 irritans, Ceratophyllus fasciatus and Hoplopsyllus anomalus. 



The two families, Pttlicida and Sarcopsyllidce, can be distinguished as follows : 

 Thoracic segments much foreshortened, coxae and femora 



of hind legs very slightly enlarged ... ... ... Sarcopsyllidce. 



Thoracic segments normal, coxae and femora of all the 



legs much enlarged ... ... ... ... ... Pulicidce. 



Family. Sarcopsyllidae (Jiggers). 



The members of this family are not confined to one host. 

 Three genera are known and tabulate as follows : 

 a. Hind coxa without a patch of spines on the inside. 



a 1 . Hind femur simple I. Dermatophilus. 



a'-. Hind femur with a large tooth-like projection near 



the base 2. Hectopsylla. 



. Hind coxa with a patch of short spines on the inside 3. Echidnophaga. 



