124 



SPECIAL EXHIBIT OF MODELS OF INSECTS AND OF PLANTS AND 

 INSECTS AFFECTING THEM. 



YELLOW FEVER MOSaUITO. 



Stcgoinijki fdscidtit Fal ). 



Enlarged model. This mosquito transmits 3'ellow fever and it is 

 now the opinion of the best-posted experts that only throug-h its bite 

 can one contract this disease. 



MALARIA MOSaUITO. 



Anophi'hs mandi})ennh Meig. 



Enlarged model. This and other species of Anopheles are the 

 only known transmitters of human maUiria. The parasitic organism 

 causing maUiria inhabits the red-blood cells of human beings. It is 

 taken with the Idood into the stomach of the mos(juito. There it under- 

 goes a sexual development, reproduces, and tiie oii'spring are carried 

 with the mosquito poison into the circulation of healthy human })eings. 



SALT MARSH MOSQUITO. 



Culex so//irif(iiis Walk. 



Enlarged model. This mosquito is not known to carry any disease, 

 but is very anno^dng at many seaside resorts. 



THE HOUSEFLY. 



3htsca (h»iii'stir(( Linn. 



Enlarged model. The housefly is not merely a nuisance, but also 

 acts as a carrier of many diseases, especially in the United States of 

 typhoid fever. 



HESSIAN FLY. 



Cecidomyla 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 

 $00,000,000. 



P^nlarged models are exhibited of the adult 11}', and of an infested 

 stalk of wheat showing the so-called " flaxseed" stage of the insect. 



Two natural-size models are exhi])ited, one representing a healthy, 

 unaffected 3'oung wheat plant to contrast with the same attacked b}^ 

 the Hessian fly; the other illustrating the effects of the attacks of the 

 Hessian fly. 



GRAPE-VINE TRUMPET-GALL. 

 Laniopfera viticola O. S. 



Model in wax of the al)U()rmal growths caused by the sting of a 

 minute dipterous insect not infrequently observed on the leaves of the 

 grape. 



