2 66 THE POPULAR SCIENCE MONTHLY 



But this familiar character of the first seen and most often seen 

 insects of the Pacific points an important moral to the student of insect 

 distribution and of insect troubles. It is the moral of man's personal 

 aid in the wide dissemination of insect pests. Wherever he goes, by 

 wagon, train or ship, he carries the pests with him, colonizes them wher- 

 ever he settles, and supports them in their new homes by his own pres- 

 ence and the presence of his domesticated animals, Ms quickly planted 

 grains and vegetables, fruits and flowers. 



So the casually inquisitive visitor to Pacific lands will find himself 

 irritated by the same kind of fleas, mosquitoes, buzzing flies and biting 

 flies, nocturnal bed-fellows, the same old croton bugs and black beetles 

 and the rest that he knows in the east and middle west. 



They have all come to California and Oregon and Washington, and 

 gone on to the Hawaiian and Samoan and Philippine Islands, just as 

 many of them came from Asia to Europe and Europe to the Atlantio 

 and went on to the Mississippi Valley in earlier years. And this emi- 

 gration and immigration by the side and with the aid of man accounts 

 for a considerable and, from the economic point of view, a very impor- 

 tant part of the Pacific insect fauna. Eor most of the worst insect pests 

 of California and the rest of the Pacific coast are imported and compara- 

 tively recently imported species. 



The most important single group of insects to the citrus and de- 

 ciduous fruit growers of California are the scale insects (Coccidse), 

 small, degenerate, specialized, wax-covered and protected sap-sucking 

 creatures, of hardly the seeming of an insect at all. The San Jose 

 scale, the cottony-cushion scale, the black scale, the soft brown scale, 

 the red orange scale, and all the rest of the scaly crew are ever threaten- 

 ing clouds on the fruit-grower's horizon. And he spends annually much 

 time, energy and money in fighting back the swiftly multiplying hordes 

 of these pests. 



Now practically all of them are natives of other lands; they are 

 man-aided immigrants into California. The San Jose scale, that once 

 threatened the whole deciduous fruit interest of California, came from 

 China about 1875. The cottony-cushion scale that similarly once 

 threatened all the citrus orchards came from Australia about 1868. 

 And the story of the coming, and settling, and finding the country good, 

 of several of the other kinds is as well known. 



But, fortunately, the economic entomologists have learned something 

 to their advantage from this kind of insect immigration. They have 

 learned deliberately to hunt for and import good bugs to fight the bad 

 ones. For example, it was discovered that the Australian cottony-cush- 

 ion scale, so dangerous a pest in this country, was not so dangerous in 

 Australia, and this because of the active efforts made there by a certain 

 kind of little black-and-red lady-bird beetle known as the vedalia. The 



