INSECTS. 185 



Family : SyrpMdsB (Hover or Hawk Flies). 



Chiefly includes brightly coloured flies, marked 

 with yellow or red and black bands or patches (Fig. 

 67), and flying rapidly with a buzzing noise. They 

 can remain suspended at the same point in the air by 

 moving their wings up and down with great rapidity. 

 A few of them resemble the bumblebee in their thick 

 covering of hair ; others, with yellow and black abdo- 

 men, look like wasps (Syrphus). The proboscis is 

 adapted for sucking, but not for piercing ; these flies 

 suck their food from flowers. They are fond of hover- 

 ing in the air in sunny places. The legless larvse vary, 

 according to species, in their habits, and consequently 

 in their structure. Some (those of the Drone Flies, 

 Eristalis) live in stagnant water; others {e.g. those 

 of Eumerus lunulatus) live in onions, which they 

 hollow out ; while some, again, develop in rotten 

 wood, etc. The maggots of the Aphis-eating Flies 

 (Syrphus), however, feed on insects, chiefly aphides, 

 which they suck out completely. They are elongated, 

 tapering in front, thickened behind, move like leeches, 

 and vary much in colour (green, yellow, brown, 

 chequered), according to the species. As they grow 

 quickly, and consequently more than one generation 

 is found each year, and as they are very voracious, 

 we must look upon them as powerful allies Ibr the 

 extermination of aphides. 



Family: Stomoxydae (Stable Flies). 



In many points the stable flies resemble ordinary 

 flies, but their mouths are adapted for piercing. Their 

 painful bites make them known to every one as 

 pests to human beings and cattle. Here belongs the 

 common Stable Fly (Stomoxys calcitrans), a form often 

 confounded with the house fly, but distinguished from 

 it by a sharp proboscis projecting at right angles, 

 besides which the abdomen is more of a yellowish 



