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224 



226 



CILiATA 



DISCOLOR 



HOWARDI 



CONFINNIS 



228 



229 



230 



CYANESCENS 



FEROX 



VARIPES 



HORRIDA 



Fig. 224-231. — Eggs of Psorophora. (Ventral side is to the right.) 



distinct circular spot covering posterior third; shape 6. Egg ( Fig. 229 ) having shell with reticulations pro- 

 of egg as in Fig. 224. In savanna and woodland nounced on anterior one-fifth. In woodland de- 

 depressions ciliata pressions ferox 



Eggshell having disc of each cell of reticulation with Egg (Fig. 230, 231) having shell with reticulations 



spot on posterior third not circular; shape of egg as not pronounced on anterior one-fifth. In woodland 



in Fig. 226. In woodland depressions. . .howardi depressions varipes 



3. Eggshell without distinct reticulations but studded with horrida 



distinct elongate spots; egg elongate (Fig. 225). 



In savanna depressions discolor MOSQUITOES AND DISEASE 



Eggshell with distinct reticulations, especially notice- In addition to their role as biters, certain mosquitoes 



able at ends 4 have been indicted as carriers of pathogens that produce 



4. Eggshell having margins of cells of reticulation form- diseases in other organisms. Below is a list of mosquitoes 



ing sharp ridges with branches radiating onto discs that have been incriminated as potential or possible vectors 



of cells; egg banana-shaped (Fig. 227). In sa- of disease-producing organisms affecting man and domestic 



vanna depressions confinnis animals in Illinois. 



Eggshell having margins of cells of re'iculation not These mosquitoes differ widely in effectiveness as vec- 



sharply ridged, the reticulations sometimes indistinct tors. Anopbeh's qinidrimjit/liitus is known to be an effec- 



in midsection of egg 5 five field vector of malaria. For many other species only 



5. Eggshell having margins of cells of reticulation clearly laboratory transmission of pathogens has been demon- 



visible over all of intact egg, which is flattened strated. and for others the association with disease has 



dorsally (Fig. 228). In hoof prints and in shade been limited to the finding of pathogens in the bodies of 



of low canopy of woodland pastures. . .cyanescens specimens. 



Eggshell having margins of cells of reticulation more Omitted from the list is Aedes aegypti. a known vector 



distinct on anterior third than on midsection of of yellow fever: neither the inosquito nor the disease is 



intact egg 6 naturalized in Illinois. 



48 



