N. H. AGRI. EXPERIMENT STATION [Bulletin 243 



THE ADULT MOSQUITO 



The adult female mosquito is the form familiar to everyone because 

 of its biting and blood-sucking habits. It is a slender, long-legged in- 

 sect, varying from three twenty-fifths to two-fifths of an inch in length. 

 It is covered with scales and hairs which give the color pattern, the 

 colors being shades of black, gray, brown, yellow, white and sometimes 

 metallic gold, silver or blue. The single pair of wings have similar 

 scales on their margins and along the veins. The males are very sim- 

 ilar to the females except that they are somewhat slenderer, have more 

 fiairy antennae, and the mouthparts are different and not suited for bit- 

 ing. From the fact that the males are incapable of piercing the skin 

 and sucking blood, it follows that they are not attracted to humans and 

 are, therefore, seldom seen, unless special search is made for them. 



The mouthparts of the female form a beak projecting from the head. 

 The part of the beak normally visible is really a tube which contains the 

 piercing lancets. This tube is slit lengthwise along its upper surface, 

 and does not enter the skin during the act of biting. When the female 

 desires to feed, the tip of the beak is placed on the skin and the lancets 

 forced in. As they penetrate, the beak bends at about its middle, allow- 

 ing the lancets to escape through the slit, except at the tip of the beak 

 which acts as a guide for them. This permits the head to approach 

 nearer the surface, forcing the piercing parts more deeply into the skin. 

 After the lancets are satisfactorily inserted, blood is sucked out through 

 a tube formed by the lancets. The irritation from a mosquito bite is 

 caused by the injection, during the insertion of the lancets, of certain 

 substances into the wound which produce the swelling, burning and itch- 

 ing. The function of these substances is to prevent coagulation of the 

 blood and so to facilitate feeding. The effect of the bite varies for dif- 

 ferent species of mosquito, and the susceptibility of different persons to 

 the bite of the same species also varies. 



The females of most of our New Hampshire mosquitoes are blood- 

 suckers, though they vary considerably in the eagerness with which they 

 seek to bite. Some species are extremely bloodthirsty and will attack 

 quickly and fearlessly, while others are slow to attack and easily fright- 

 ened off. Nearly all of the blood-sucking species will attack man, but 

 a number of them seem to prefer the larger mammals such as horses or 

 cows, and one species is known to attack only cold-blooded animals such 

 as frogs. All male mosquitoes, and the females of a number of species, 

 feed only on the nectar of flowers and plant juices; these substances may 

 also form a part of the food of the blood-sucking females. 



Many mosquitoes hide during the day in sheltered places, such as long 

 grass or shrubbery, becoming active at dusk, but some Qy both by day 

 and by night and will bite readily in the daytime, particularly if their 

 haunts are invaded. Some species are found only in the vicinity of 

 their breeding places, others may fly a mile or more from their place of 

 origin, while some of the salt-marsh species sometimes migrate widely. 



