SPECIAL EXHIBITS. 
ENLARGED MODELS OF INSECTS, AND OF INSECTS AND INJURED 
3 PLANTS. 
MALARIA MOSQUITO. 
Anopheles maculipennis Meig. 
Enlarged model. This and other species of Anopheles are the only known trans- 
mitters of human malaria. The parasitic organism causing malaria inhabits the red- 
blood cells of human beings. It is taken with the blood into the stomach of the 
mosquito. There it undergoes a sexual development, reproduces, and the offspring 
are carried with the mosquito poison into the circulation of healthy human beings. 
YELLOW FEVER MOSQUITO. 
Stegomyia fasciata Fab. 
Enlarged model. This mosquito transmits yellow fever, and it is now the opinion 
of the best-posted experts that only through its bite can one contract this disease. 
SALT MARSH MOSQUITO. 
Culex sollicitans Walk. 
Enlarged model. This mosquito is not known to carry any disease, but is very 
annoying at many seaside resorts. 
THE HOUSE FLY. 
Musca domestica Linn. 
Enlarged model. The house fly is not merely a nuisance, but also acts as a carrier 
of many diseases, especially of typhoid fever in the United States. 
HESSIAN FLY. 
Mayetiola destructor Say. 
One of the most injurious enemies of wheat in the northern and central States. 
The larva attacks the stem. The average yearly damage to the wheat industry in 
this country from this insect is $60,000,000. 
Enlarged models of the adult fly, and of an infested stalk of wheat showing the 
puparium or so-called ‘‘flaxseed,’’ which encloses the pupa stage of the insect. 
Two natural-size models, one representing a healthy, unaffected young wheat 
plant to contrast with the same attacked by the Hessian fly; the other illustrating 
the effects of the attacks of the Hessian fly. 
THE SILKWORM. 
Bombyx (Sericaria) mori Linn. 
Enlarged model of the larva, showing its complete anatomy; the muscles, nerves, 
tracheze, viscera, the silk apparatus in its whole extent, the silk-secreting gland, and 
the gland discovered by Auzoux, which secretes a liquid the use of which is most 
probably to convert the silky matter into insoluble threads. In one of the prolegs 
_may be seen the muscles which move the claws and sucking disks which enable the 
animal to walk with its true feet in the air. 
Enlarged models of the moths, male and female. In each model is shown the 
atrophy of the digestive tube and the development of the marvelous organs by which 
the species is perpetuated. (After Auzoux. ) 
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