outdoor privy with a seldom closed door is built over it, mosquitoes will 

 breed all summer in the fluid contents of the vault and of course will 

 infest all the adjacent houses. 



In such cases a teacupful of kerosene poured into each vault at inter- 

 vals of a month or less would greatly decrease the annoyance from 

 mosquitoes, if it did not altogether prevent it. This is a case where the 

 cooperation of neighbors is most essential ; every householder in a given 

 neighborhood should see that his vault is treated with kerosene regularly' 

 and often. The cost is so trifling that it need not be considered. 



Where, as is the case at many country homes, rain water is collected 

 in barrels or hogsheads, for one purpose or another, mosquitoes may 

 and do breed in numbers in such vessels. If the water as used be drawn 

 from the bottom of the cask, it will do no harm to pour in a little kero- 

 sene, since the oil will not be drawn out with the water. At all events, 

 such receptacles should be covered at night to prevent egg-laying. 



The question. What is the best way to cover with kerosene the sur- 

 face of a pool of some size? is apparently needless, since the operation 

 is obviously simple, but such a question has been asked of the Division. 

 Simply pouring the oil on from any point of the shore will answer tol- 

 erably well, since it will spread of itself, but if for any reason it is desired 

 to coat the pool rapidly with kerosene, it may be advisable to spray the 

 oil through a spraying nozzle, either from the bank or from a boat. The 

 method of application will vary with each case, but in the class of pools 

 which can be most advantageously treated, namely, those of small size, 

 the oil can be well spread b}'' throwing it on to windward with a wide 

 sweep of the arm. 



II.— FLEAS. 



Judging from the specimens of fleas sent to the Division of late years, 

 with complaints of houses infested by them, the human flea {Pulex 

 irrifans) is not the species most likely to occur in great numbers in 

 dwelling houses, but rather the common cosmopolitan flea of the dog 

 and cat (Pulex serraticeps) . A house may become infested with this 

 species, even though no domestic animals be kept, for a visitor at a 

 house where such pets are maintained may be the means of carrying 

 home with him one or two female fleas which will stock his own prem- 

 ises. Of course where a pet dog or cat is kept the source of the infes- 

 tation is manifest. 



The worst cases of infestation reported to this Division were where 

 houses had been temporarily unoccupied during the summer. Such 

 houses often become more or less damp, and as a rule the customarj' 

 sweeping of the floors is interrupted, thus furnishing the very conditions 

 under which, as we shall see, fleas most readily propagate. 



The eggs of Pulex serraticeps are deposited among the hairs of cats 

 and dogs, but as thej^ are not attached to the hairs, numbers drop off 

 whenever the infested animal moves or lies down. For experimenters 

 who desire to follow out for themselves the life history of the species, 

 an easy way to collect the eggs is therefore to lay a strip of cloth or car- 

 pet for the animal to sleep upon, and afterwards to brush the cloth into 

 a receptacle, in which the eggs will be found in numbers if the animal 

 is infested. In this lies a hint for the housekeeper who would keep a 

 pet dog or cat and yet avoid an outbreak of fleas in the house. Provide 

 a rug for the cat or the dog to sleep on and give this rug a frequent 

 shaking and brushing, afterwards sweeping up and burning the dust 

 thus removed. As all the flea eggs on an infested animal will not, how- 



