British BLooDsrcKKKs 



251 



hand by clenchinj:^ your fist hard, you will find 

 that shf cannot anv lonj^er withdraw her man- 

 dibles ; they arc cau,^ht fast in your Hcsh by their 

 own harpoon-likc teeth, and there she must stop 

 accordinj^ly till you choose to release her. If you 

 then kill her in the usual manner, bv a smart slap 

 of the liand, you will see that she is literally full (>f 

 blood, havinj4 suckerl a i^ood drop (;f it. 



The hununinj4 sound itself by which the mos- 

 quito announces her approaching^ visit is produced 

 in two distinct manners, 'i'he deeper notes which 

 go to make up her droniniLi song are duv to the 

 rapid vibration of the female insect's wings as she 

 flies ; and these vibrations are found by means of 

 a siren (an instrument which measures the fre- 

 quency of the waves in notes) to amount to about 

 3000 in a minute. The mo>e|uito's wings must, 

 therefore, movi' with this extraordinarv rapidity, 

 which suiticientlv accounts for the ditficultv we 

 have in catching one. Hut the higher and shriller 

 notes of the complex melodv an' due to special 

 stridulating organs situated like little drums on the 

 openings of the air-tubo ; for the adult mosquito 

 breathes no longer by om- or two aii-entranccs on 

 the tail or back, like the larva, but bv a number of 

 spiracles, as they are called, arranged in rows along 

 the sides of the body, and couunmucating witli the 

 network of internal aii-chambers. 'I'he cui"i(<^is 

 mosquito music thus generated bv the little drums 

 serves almost bevond a doubt a> a means of attract- 

 ing male mosquitoes, for it is known that the long 

 hairs on the antemiic of the males, shov»ii in Xo. 9, 



