374 



Marvels of Insect Life. 



erectly and adhere one to another, so that finall\- they form a tiny, boat-shaped mass, 

 which floats safely on the water, and the emerging grubs, a few days later, have 

 only to push open a sort of trap in the floor to find themselves in the water. 



The proboscis or piercing and sucking organ of the gnat is to the unaided eye 

 a simple instrument, and we have spoken of it as a stiletto ; but viewed through 

 the microscope it is seen to be anything but simple in its structure, for it has no 

 fewer than seven separate parts. Two of these are the lengthened upper and lower 

 lips, which form a protecting case for the more delicate cutting needles. This outer 

 sheath does pierce the skin, but having a sort of knee-joint it partly doubles up 

 to allow the needles to enter, whilst by pressing its lobed tips against the skin it 



steadies the action 

 of the other parts, 

 which are a modi- 



fication 



jaws 



Insects. 



of the 



of biting 



Now the 



whv the 



Phoio by'_ [H. S. C/icavin. F.R.M.S. 



The Gnat Emerges. 



When full devolopment is almost reached, the gnat-chrysalis floats, back upwards, at the surface, and 

 its skin splits behind the head. The gnat wriggles partly out, gets its legs out, and balancing itself 

 on the tips of these, withdraws its long wings and the hind-body. It has to maintain itself in this 

 precarious position until its parts are sufficiently firm for flight. jMagnified about ten times. 



reason 

 male gnat or mos- 

 quito does not 

 attack man and 

 other animals is 

 not necessarily that 

 it is of more peace- 

 ful disposition, but 

 rather that it has 

 not the power — the 

 piercing and cutting 

 implements are 

 undeveloped. 



Although our 

 common gnat can 

 make itself exceed - 

 ingh^ unpleasant 

 through the irrita- 

 tion and disfiguring 



swellings 



produced 



by its blood-sucking, it has not yet been detected as a carrier and transmitter of 

 disease ; but a member of the same genus, ^ the brown mosquito so prevalent in 

 Southern India, is the transmitter of elephantiasis. Several allied species, but 

 belonging to another genus, ^ are the carriers of malaria, which they accomplish 

 by sucking up the germs with the blood of an already afi^icted person, and 

 inoculating a healthy person with them when they take another meal. The 

 parasite runs through its course of development in the body of the anopheles 

 mosquito and stores the Insect's salivary glands with a fresh stock of germs for 

 dissemination. 



1 Culcx latigans. 



2 Anopheles. 



