MOSQUITOES AND FLEAS. 



25 



Laboulbeiie describes carefully the pretty, oval, waxy white or 

 opaque, porcelaiu-colored, smooth egg, wliich reaches 0..j mm. in 

 leugth. He describes the external appearauce of the larv;e and recites 

 their extremely rapid movements, which are made by means of the 

 bristles with which they are furnished, and particularly by means of 

 the tu])ercle and the hair-like spines below the head. Tie i)laced larvie 

 upon dust, with birds' feathers mixed with dried blood, upon which 

 they developed perfectly. Others were put on the sweepings of a room, 

 and developed just as well. Laboulbeue at first believed that blood 

 was necessary for the nourishment of the larvte, the reddish-colored 

 contents of the digestive tract making him think so; but he found they 

 would flourish and complete their metauiorphoses in sweepings in which 

 there was no trace of blood. He concluded that all that has been said 

 on Fulex irrifans nourishing its young on dried blood is very problem- 



FiG. 5. — Pulex serraticeps ; a, egg; b, larva in cocoon; c, pupa; d. adult; e, mouth-parts of same from 

 side: /, labium of sauie from below: 'j. auteuna of same— all enlarjred (original). 



atical. In his opinion the larvie of the cat Hea for the most part live 

 upon the ground in spots where cats stay, and that they live in the 

 dust in the cracks of the floor. The cocoon he described as ovoid, 

 almost rounded, brown and granular, because it is covered with dust, 

 delicate, bat difficult to open, attached by one surface. It is about 

 2.5 mm. by 2.75 mm. The only statement in the article regarding the 

 length of the different stages is to the effect that the i)upal condition 

 lasts from one to two weeks. 



Mr. Simmons found the eggs upon a cloth upon which a dog had 

 been sleeping, in the midst of a dust composed of fragments of cuticle, 

 hairs, fibers, and pellets of dried blood, the last being probably the nat- 

 ural excreta of the fieas. In fifty hours most of the eggs hatched. The 

 larva? are described, and the statement is made that in seven days they 

 began to spin their cocoons. They remained in the cocoons eight days, 



