These are two illustrations, from among hundreds which might be cited, of the very practical value of entomological knowledge.
+--------------------------------------------------------------+ | | | EXPLANATION OF PLATE XXXI | | | | 1. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _lucia_, Kirby, ♂. | | 2. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _marginata_, Edwards, ♂. | | 3. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _marginata_, Edwards, ♀. | | 4. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _nigra_, Edwards, ♂. | | 5. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _violacea_, Edwards, ♂. | | 6. _Lycæna pseudargiolus_, Boisd.-Lec., | | ♂. | | 7. _Lycæna pseudargiolus_, Boisd.-Lec., | | ♀. | | 8. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _neglecta_, Edwards, ♂. | | 9. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _neglecta_, Edwards, ♀. | | 10. _Lycæna pseudargiolus_, Boisd.-Lec., | | var. _piasus_, Boisduval, ♂. | | 11. _Lycæna dædalus_, Behr, ♂. | | 12. _Lycæna dædalus_, Behr, ♀. | | 13. _Lycæna heteronea_, Boisduval, ♂. | | 14. _Lycæna heteronea_, Boisduval, ♀. | | 15. _Lycæna sæpiolus_, Boisduval, ♂. | | 16. _Lycæna sæpiolus_, Boisduval, ♀. | | 17. _Lycæna lygdamas_, Doubleday, ♂. | | 18. _Lycæna lygdamas_, Doubleday, ♀. | | 19. _Lycæna sagittigera_, Felder, ♂. | | 20. _Lycæna sagittigera_, Felder, ♀. | | 21. _Lycæna sonorensis_, Felder, ♂. | | 22. _Lycæna sonorensis_, Felder, ♀. | | 23. _Lycæna shasta_, Edwards, ♂. | | 24. _Lycæna shasta_, Edwards, ♀. | | 25. _Lycæna melissa_, Edwards, ♂. | | 26. _Lycæna melissa_, Edwards, ♀. | | 27. _Lycæna acmon_, Dbl.-Hew., ♂. | | 28. _Lycæna acmon_, Dbl.-Hew., ♀. | | 29. _Lycæna comyntas_, Godart, ♂. | | 30. _Lycæna comyntas_, Godart, ♀. | | 31. _Lycæna ammon_, Lucas, ♀. | | 32. _Lycæna marina_, Reakirt, ♀. | | | | [Illustration PLATE XXXI.] | +--------------------------------------------------------------+
The annual loss suffered by agricultural communities through ignorance of entomological facts is very great. Every plant has its insect enemy, or, more correctly, its insect lover, which feeds upon it, delights in its luxuriance, but makes short work, it may be of leaves, it may be of flowers, it may be of fruit. It has been estimated that every known species of plant has five or six species of insects which habitually feed upon it. Where the plant is one that is valuable to man and is grown for his use, the horticulturist or the farmer finds himself confronted, presently, by the ravages of these creatures, and unless he has correct information as to the best manner in which to combat them, he is likely to suffer losses of a serious character. We all have read of the havoc wrought by the Kansas locust, or grasshopper, and of the ruin brought about by insects of the same class in Asia and in Africa. We all have heard of the Hessian fly, of the weevil, and of the army-worm. The legislature of Massachusetts has in recent years been spending hundreds of thousands of dollars in the attempt to exterminate the gipsy-moth. The caterpillar of the cabbage-butterfly ruins every year material enough to supply sauer-kraut to half of the people. The codling-moth, the little pinkish caterpillar of which worms its way through apples, is estimated to destroy five millions of dollars' worth of apples every year within the limits of the United States. And what shall we say of the potato-bug, that prettily striped beetle, which, starting from the far West, has taken possession of the potato-fields of the continent, and for the extermination of which there is annually spent, by the agricultural communities of the United States, several millions of dollars in labor and in poisons?