INSECT PESTS OF THE HOUSE. 343 



is usually attained in less than two weeks ; they then pass two 

 more weeks in the pupal stage, when the perfect insect appears. 

 When dogs are badly infested by them, the use of common olive- 

 oil is recommended. This should be well rubbed into the hair 

 and over the skin, being allowed to remain for half an hour, 

 when it should be washed out with the best yellow soap and 

 lukewarm water. Dalmatian insect-powder has also been found 

 efficacious. This powder can be rubbed into the hair, and it can 

 be sprinkled around their kennels. It is not, however, best to use 

 it on cats, but possibly it might do no harm 

 to sprinkle it around their sleeping-places. A 

 better plan is to have the cat's bed made of 

 shavings or some such material that can often 

 be replaced, the old bedding being carefully 

 taken up and burned. 



Some years ago there were on exhibition a 

 number of so-called educated fleas, and it is 

 thought by some people that the intelligence 

 of fleas must be very great if they can be 

 trained in this way ; but an article by Mr. W. FlG . 6.-larva op Flea. 

 H. Dall, in the American Naturalist, a few 

 years ago, showed that in every case the motions made by the flea 

 were caused, not by the training it had received, but by the strug- 

 gles made in its efforts to escape. 



House-Fly (Musca domestica). — Familiar as we all are with 

 this insect in its mature state, it will be found that to many its 

 history before it appears in our houses is still very obscure, and 

 until some years ago, when Dr. Packard made a study of its life- 

 history, naturalists, too, were somewhat unfamiliar with its early 

 stages of growth, and to him we are indebted for the following 

 facts : 



"We find the flies most annoying and abundant in the hot dog- 

 days of August, and, unless the greatest care is taken, our rooms 

 are filled with them, even though we maybe some distance from a 

 stable, where the desired food for the young is found. The eggs are 

 laid in bunches in manure, often buried out of sight, and, the con- 

 ditions being favorable, they are hatched in twenty-four hours. 

 The worm or maggot has no legs, and, after changing its skin, 

 appears larger, though otherwise remains about the same in ap- 

 pearance. After two or three days it again sheds its skin, and in 

 this stage of development it remains two or three days longer. 

 It then transforms into a chrysalis, in which state the body con- 

 tracts somewhat and becomes brown and hard, and, after six or 

 seven days, the perfect fly appears and lives for five or six weeks, 

 perhaps longer. A few flies probably live over the winter in crev- 

 ices of buildings until the warm spring days bring them out. 



