72 Objects for the Microscope. 



HEAD OF DRONE-FLY, OR HELOPHILUS. 



This so nearly resembles the Rhingia that little need be 

 added in explanation, except of the fly itself, which is one 

 of the Syrphidee, nearly related to the Rhingia. The Helo- 

 philus is that large black and yellow fly so common in the 

 autumn on Michaelmas Daisies, often mistaken for a Wasp, 

 as it makes a loud humming noise and is very intent upon 

 its feast. It passes through a greater change than most of 

 the fly tribe ; for it lived and fed in the foulest sewer as a 

 rat- tailed larva which is yery curious in its manner of 

 breathing. This larva has a long retractile tail, with the 

 action of a telescope, capable of immense extension to reach 

 the surface of the water or mud for air. The body being 

 very transparent, the tracheal vessel is distinctly seen in a 

 wavy line the whole length of the tail. 



HEAD OF ERISTALIS, 



differs only from Helophilus in having a black hairy body, 

 more like a Bee. The antennae are very beautiful. 



HEAD OF TIPULA. 



This favourite and beautiful preparation is the head of 

 our familiarly called Daddy-long-legs. The colour adds to 

 the beauty of the lacework eye, and the fine antennae, simple 

 yet varied in the length of the joints, which are each 

 slightly hairy. The palpi have four joints, and bend over 

 the broad fleshy proboscis, in which large trachea are 

 distinctly seen. These Tipula? are very destructive in the 

 grub state. The female deposits her eggs in deep burrows 

 by means of a long ovipositor, consisting of four pieces ; 

 two of them bore like an auger the required hole in the 

 earth, and the other two join and conduct the egg to its 

 appointed place. When the larva hatches it has two short 

 horns on its head, several fleshy conical appendages on the 

 abdomen, and two very strong mandibles working against 

 two horny convex dentated plates. Very destructive are 

 they to the farmer's grass land, often destroying hundreds 

 of acres in England and France. The more, therefore, of 

 these beautiful heads that are thus prepared the better. 



