ENTOMOLOGY. 253 



animals based apon the author's own studies and those of others. The 

 difficulty of accurately defining parasitism is referred to, and the plans 

 followed by Lueckhart, Looss, Blanchard, Neumann, Kailliet, and others 

 in the discussion of the subject of parasitism are indicated. 



The plan adopted by the author is to treat the different species in 

 their zoological order so that related forms may be kept more or less 

 together and repetition avoided, discussing each species as fully as may 

 be, mentioning its past history, the extent of its injuries, its habits, its 

 life history, and finally the proper methods of preventing or relieving 

 its injuries. This plan is followed through six chapters, beginning with 

 the Diptera and ending with the Linguatulina. The seventh chapter is 

 devoted to preventive measures and discusses insect icidal substances, 

 the methods of application of remedies, the direct capture or destruc- 

 tion of insects, the renovation of henhouses, and the subject of dimi- 

 nution by washes and dips. The eighth chapter gives a list of parasites 

 classified according to their host, beginning with man, the apes, and the 

 monkeys, and ending with pigeons, geese, and swans. A bibliography 

 of about 123 titles constitutes the last chapter. 



The introductory chapter discusses the grouping of the parasitic in- 

 sects, the general life history of parasites, the origin of the parasitic 

 habit, the results of parasitism upon the parasite, the distribution of 

 parasites, the effect of parasites upon the host, the losses due to para- 

 sites, and popular notions concerning parasites. 



Under the last head observations are reported which tend to show 

 that the popular notions that poor and weak animals are more subject 

 to attack of parasites than those in good condition and that white 

 rather than dark cattle are infested are erroneous. The somewhat 

 generally observed fact that mosquitoes, flies, lice, and other insects 

 appear to select certain individuals in preference to others may be 

 accounted for by a difference in the character of the secretions, in the 

 structure of the skin, or in the size of the hair. 



As in the case of other insects, it is usually much easier, the author 

 states, to prevent injuries from parasites than to remedy them. Know- 

 ing that certain species are incapable of flight and must depend for 

 their distribution upon the direct association of infested animals, the 

 breeder may simply isolate his uninfested animals from his infested 

 animals, or rub them with some substance obnoxious or destructive to 

 the pests. This is obviously more simple than the employment of 

 washes and dips to destroy parasites upon animals already infested. 



Diptera (pp. 24-140). — The author discusses mosquitoes and gnats 

 (< 'ulichke), midges (Chironomidw), flies (Simuliidse, Tabanida*, Leptidse, 

 Qestridse, and Muscidse), and forest flies and ticks (Hippoboscida^ and 

 Nycteribiidfe). Considerable space is given to a discussion of buffalo 

 gnats and botflies. 



Siphonaptera; Fleas (pp. 141-15.*)). — This includes descriptions of the 

 jigger flea or chigoe (Sarcopsylla penetrans), the hen flea (S. gallinacea), 



