COLLECTING AND PRESERVING INSECTS BANKS. 3 



piece, the femur; then the tibia; and beyond that the tarsus. The 

 latter is of from one to five joints, and ends in one or two claws. The 

 top of an insect is called the dorsum, and the lower surface the venter; 

 the sides are the pleura. Insects do not breathe through the mouth, 

 but by means of tiny apertures called spiracles placed along the 

 sides of the body, mostly upon the abdomen. Their mouth-parts, or 

 cibaria, present a great diversity of structure and use. Commonly, in 

 biting insects, there is a pair of hard jaws, or mandibles; below them 

 a pair of maxilla?, bearing a pair of maxillary palpi (short, jointed 

 appendages) ; and an upper and a lower lip. The latter also bears a 

 pair of palpi, the labial palpi. In many forms there is an unpaired 

 central piece, the tongue or hypostome. In many insects these parts 

 or some of them are modified to form a sucking apparatus. The sight 

 of insects is very different from our own, and most insects apparently 

 do not notice objects a few feet away from them. The sense of smell 

 is very acute, and serves to attract them to their food, to the food 

 plant of the larvse, or to their mates. It is usually considered that 

 the antennas bear the organs of smell. Many insects make sounds: 

 therefore they must hear. The organs which effect audition afe, how- 

 ever, known only in a few groups and are very different from our ears. 

 Most insects do not live long in the adult or winged stage; some 

 only a few days, comparatively few more than one year. Some, 

 however, spend several years in the larval and nymphal conditions. 

 When once an insect acquires wings it does not increase in size, so 

 that the little flies are not, as is often supposed, the young of the 

 big ones. 



IMPORTANCE OF ENTOMOLOGY. 



When the early entomologists wrote upon their favorite theme it 

 was customary to apologize for studying such unimportant things as 

 insects, and to justify their actions by quotations from the Bible, or 

 reflections on the insignificance of human life. These remarks of the 

 ancient writers are as pertinent as ever, but, thanks to the more en- 

 lightened spirit of this scientific age, are no longer necessary. The 

 losses caused by insects to the crops of the country are beyond the 

 appreciation of man's mind. The cost of the damage by a single 

 species often runs up into millions of dollars. Likewise the impor- 

 tance of the beneficial species which prey on and destroy the injurious 

 forms is now, through such striking examples as the Vedalia ladybird, 

 becoming familiar to all. Beside the two notably useful insects — the 

 honey bee and the silkworm — the lac-insects, cochineal, blister flies, 

 ink galls, etc., are of direct benefit to mankind. 



The role of insects in the transmission of disease has, in recent years, 

 assumed a tremendous economic importance. The cattle tick was for 

 years the principal exponent of the possibilities along this line, but 

 88552— Bull. 67—09 2 



