4 BULLETIN 67, UNITED STATES NATIONAL MUSEUM. 



now a dozen or more ticks are known to disseminate diseases. One 

 particular mosquito, Anopheles maculipennis , is the main factor in 

 malaria, while another species, Stegomyia calopus, is equally as respon- 

 sible for yellow fever. This small family of insects, entirely neglected 

 a few years ago, is now studied by dozens of entomologists. A flea 

 {Xenopsylla clieopis) is now connected with the distribution of the 

 bubonic plague. The house fly, that formerly was thought useful in 

 the destruction of decaying matter, is now known, through its deposi- 

 tion of flyspecks on our food, to be concerned in the spread of typhoid 

 fever, and a possible factor in several other diseases. Undoubtedly 

 other insects will be connected with the spread of disease as the field 

 of medical entomology is daily widened in extent and importance. In 

 the Tropics a large number of diseases are distributed by insects. The 

 Nagana disease of South Africa is distributed by the Tsetse fly; the 

 sleeping sickness by a similar species of fly; the Surra of India by 

 horse flies, etc. Indeed, the wild animals of the forests have lost 

 their terrors, and it is the minute creatures that are full of danger. 



In the number of species, insects far exceed all other animals taken 

 together. Estimates made by well-known entomologists of the num- 

 ber of insects in the world have ranged all the way from two to ten 

 millions of kinds. More than 35,000 forms of insects are already 

 known from our country and this is probably not half of the entire 

 number. Recently a famous European entomologist, Dr. A. Hand- 

 lirsch, has figured out that there are about 385,000 species of insects 

 described from the entire globe. Of them 172,500 are beetles; 60,000 

 moths and butterflies; 55,000 ants, bees, and wasps; 44,000 two- 

 winged flies, and 33,000 true bugs. One single family of the beetles, 

 the weevils, numbers 23,000 species. And, moreover, fully 6,000 

 species are described as new by entomologists each } T ear. 



Aside from their great numbers or their agricultural or their medical 

 importance, insects are a source of study, of interest, of pleasure and 

 recreation to an ever-increasing number of naturalists year after year. 

 The pleasure in securing the many beautiful forms, the interest in 

 studying the remarkable structures, or the charm in unraveling a 

 peculiar life history has attracted many a busy man as a means of 

 relaxation from the ordinary duties of life. It affords a recreation at 

 once healthful and instructive. The increasing interest in outdoor life 

 and in nature study constantly brings insects into prominence as a 

 group easily observable and replete with interest. All of these factors 

 have combined to give insects such importance that there are now in 

 this country over 2,000 members of the brethren of the net. 



