Mosquitoes 



have been seen puncturing the chrysalis of a butterfly, and they 

 have been seen swarming about turtles when the latter are on 

 land. The larvae on the contrary, feed upon all sorts of minute 

 organisms floating in the water, such as the spores of alg?e and 

 minute aquatic animals. They are 

 all furnished with many bristles at 

 the mouth, and these bristles are 

 kept in constant vibration drawing 

 particles floating or in suspension 

 in the water into the mouth cavity. 



Five genera of mosquitoes are 

 represented in this country, namely 

 Anopheles, Aedes, Megarhiniis, 

 Psorophora and Culex. Most of 

 our species belong to the genus 

 Culex, and one species of this genus 

 has been selected for the typical 

 life history which is given. 



The mosquitoes of the genus 

 Anophe/es are the ones which are 

 responsible for the transfer of ma- 

 laria. The micro-organism of malaria is a protozoon which in 

 the human being inhabits the red-blood corpuscles. It undergoes 

 a sporulating development in the red-blood corpuscles, the spores 

 being thrown into the blood serum afterward entering other 

 blood corpuscles extracting their red coloring matter and destroy- 

 ing them. The full life round of the malarial parasite, however, 

 is not completed until it has been taken with the blood of a 

 human being into the stomach of a mosquito of the genus 

 Anopheles. Here, and here only, is the sexual generation of the 

 parasite developed. Certain of the parasites which undergo no 

 development in the human body, when they are brought into the 

 stomach of the Anopheles continue a sexual development, unite 

 and give birth to elementary forms, known as blasts, which pene- 

 trate the stomach wall of the mosquito, enter the salivary 

 glands, and are thus with the poison directed into the body 

 of the next human being punctured bv this mosquito. 



We have in the United States three species of mosqui- 

 toes of this malarial genus Anopheles, namely A. maculipennis^ 

 quadrimaculatus=claviger, A. punctipennis and A. crucians. 



Fig. 55. — Anopheles maculipennis: 



Egg from below at left, from above 



at right^greatly enlarged. 



(Author's ilhtstration.) 



