228 OUR HOUSEHOLD INSECTS 



house-fly and the blow-fly sip their liquid nutriment; 

 yet both are but extreme modifications of the same plan, 

 the rasping and sucking elements being carried to the 

 summit of perfection in the one case, and the boring 

 or piercing ones in the other. Many intermediate forms 

 may be seen, as in the drone-flies, breeze-flies, wasp-flies, 

 and others which have no popular names, and a very 

 interesting series showing the gradations might without 

 much difficulty be prepared. 



Now how is this collection of weapons used ? The 

 little inject drops gently and daintily down on to the 

 spot it has selected for its attack, and the descent of 

 so light and airy a being is likely to leave the victim 

 unconscious of its presence, unless he has actually seen 

 it settle. Then the proboscis is pointed downwards, and 

 the tiny lips that form its tip pressed against the flesh. 

 The bristles within the gutter-like sheath being then 

 pressed together into one solid boring implement, their 

 common tip is forced down on the flesh, and as they 

 enter the wound, the trough in which they were lying 

 separates from them in the middle, and becomes bent 

 towards the insect's breast, the two little lips all the 

 while holding on tight. The greater part of the length 

 of the stilettos is then plunged into the victim's flesh, 

 and the blood is drawn up the fine interstices of the 

 composite borer. The wound, though six instruments 

 are concerned in making it, is extremely minute. 



So far, our description has concerned the proboscis of 

 the female gnat or mosquito only. That of the male 

 is somewhat different. There is still the straight, stick- 

 like labium, but the palpi are greatly elongated, running 

 along by the sides of the tubular proboscis as far as, or 

 even beyond, its tip, and tufted at the end. A fine 

 rod-like organ may be separated from the labium, but 



