PART III. 

 ANIMAL PARASITOLOGY. 



CHAPTER XV. 



GENERAL CONSIDERATIONS OF CLASSIFICATION AND 



METHODS. 



ANIMALS that are in all respects alike we term a Species. Of course 

 the male and female of a species may be very unlike, but as a result of 

 mating they produce young having characteristics similar to the 

 parents. Now, if, as in the case of the mosquitoes causing yellow fever, 

 we find some with straight silvery lines and others uniformly showing 

 crescentic silvery bands about thorax, yet resembling each other closely 

 in the respect of being dark, brilliantly-marked mosquitoes, we should 

 consider them as being separate species with a certain relationship to 

 which the term Genus is applied. In naming a species we always first 

 write the name of the genus, which has a Greek or Latin name, com- 

 mencing with a capital, and follow with the specific term, which latter 

 commences with a small letter. Thus we designate the dark silver- 

 marked mosquitoes as belonging to the genus Stegomyia; those 

 showing the characteristics of curved silver bands on dorsal surface of 

 thorax we designate as Stegomyia calopus ; the species with the straight 

 silver lines we call Stegomyia scutellaris. 



Again, certain genera show resemblances which enable us to make 

 broader groupings to which we apply the name Subfamily. Thus the 

 genus Stegomyia and the genus Culex have the similar characteristics of 

 palpi in the female being shorter than the straight proboscis ; we there- 

 fore classify all species of Stegomyia and all species of Culex under the 

 designation Culicinae. The name of a subfamily ends in "inae." Now, 

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