308 INSECTS AFFECTING MAN AND HOUSEHOLD 



moistening pyrethrum powder and moulding the same into a 

 cone the size of a chocolate drop, allowing it to dry and applying 

 a match to the apex of the cone. This stupefies or repels the mos- 

 quitoes, although it may not kill them. Affected mosquitoes 

 should be swept up and burned. Chinese "joss sticks" burned 

 in sleeping rooms act as repellents. 



House Fleas. Where cats or dogs are kept or have been kept, 

 the household is apt to be troubled by one or both of these insect 

 pests (Pulex irritans L. and Ctenocephalus canis Curtis). They 

 are almost too well known to need description. The first-named 

 species is common throughout Europe and quite plentiful in Cali- 

 fornia, and it also occurs in localities in the Middle West. The 



last named, which is the com- 

 mon cat or dog flea, is more 

 common in the house than the 

 human flea (Fig. 316). A 

 house which has lodged a cat 

 or dog and been left unoccu- 



FIG. 316. At left, human flea, greatly enlarged. At right, egg (a) and larva (b) of dog and 

 cat flea, much enlarged. 



pied for a time may become badly infested. One can hardly 

 realize the unending appetites and activity of these insects unless 

 he has suffered therefrom. 



Life History. The female deposits, on an average, eight hun- 

 dred eggs during its lifetime, laying from twelve to twenty at 

 one time. These are placed in cracks of floors, dark corners, or 

 where dead organic matter is left undisturbed for a time. In 

 warm weather they hatch in about six days. The white larvas 

 have antennae or feelers but no eyes, which is unusual for immature 

 forms of insects. They soon become yellowish, later brownish, 

 and reach full growth in eleven days, thereupon forming a loose 

 cocoon of dust, etc., in which they transform to pupa. The adult 

 appears in from ten to twelve days. Several broods occur during 

 the warm weather. 



