186 SCHOOL ENTOMOLOGY 



weather the complete life cycle may be completed in two 

 weeks and as each egg-mass contains from 75 to 200 eggs, 

 mosquitoes multiply very rapidly. It is only the females 

 which have piercing mouth-parts enabling them to "bite," 

 the mouth-parts of the males being more feeble and being 

 used for sucking vegetable juices, which are, doubtless, the 

 natural food of both sexes. The males may be distinguished 

 from the females by their feathery antennae. 



The best means of mosquito control is to prevent the 

 development of the larvae, which may be done by abolishing 

 their breeding places or so treating them as to kill the larvae. 

 In many sections where mosquitoes have been a plague, 

 notably in New Jersey, large areas have been drained or 

 filled at public expense for this purpose. Usually many 

 breeding places may be found which can very easily be 

 eradicated. The introduction of fish will aid in ridding 

 ponds of mosquitoes. Where this is not possible breeding 

 places should be treated with low-grade kerosene, fuel-oil, or 

 some larvacide, which will destroy the larvae and pupae 

 through their breathing tubes. Use twelve ounces of kero- 

 sene to fifteen square feet of surface, or one-half cupful for a 

 barrel. Houses should, of course, be screened and in some 

 places it will be necessary to screen verandas with fine-meshed 

 screening. Rain-barrels, cisterns and other water receptacles 

 should be screened. Possibly the best repellent for mos- 

 quitoes is oil of citronella and for their bites nothing is better 

 than ammonia. Where they have become over-numerous 

 in a room they may be destroyed by burning pyrethrum 

 powder (page 178). Rooms and cellars may also be fumi- 

 gated with "culicide" (38) or by burning sulphur (page 336). 



115. Fleas. The fleas (29, 51) most commonly annoying 

 in houses are the common cat or dog flea. * The adults are 



* Ctenocephcdus canis Curt. Order Siphonaptera, see page 38. 



