24 



Marvels of Insect Life. 



aeration of the blood, 

 for the creature is without 

 the spiracles or breathing 

 holes of land Insects. 



When this aquatic 

 larva is fully grown, it 

 leaves the water and 

 searches for a suitable 

 spot in which it can form 

 a cell. Here it changes to 

 a chrysalis, which shows 

 the wings and other 

 characters of the perfect 

 Insect. In this stage it 

 is quite inactive, but after 

 an interval it again casts 

 its skin and emerges fully 

 developed as an alder-fly. ^ 

 It is everywhere common 

 in the neighbourhood of 

 water. There is a second 

 species "^ of darker hue, 

 which appears to be less 

 common, though from their 

 general similarity it is 

 probable that the two 

 are frequently confused. 

 Though these flies measure 

 only an inch across the 

 expanded wings, there are 

 near relations (in another genus ^) in America and India which are much 

 larger, and, from the enormous development of jaws, of formidable appearance. 

 These jaws are equal in length to the united measurement of the fore-body 

 and hind-body. In their earlier stages their forms and habits are much like 

 those of the alder-fly ; and the same may be said for the ultimate stage, 

 except that the extraordinary jaws so well shown in our photograph on page 21 

 have no counterpart in the alder-fly, and their purpose has not yet been 

 made plain. 



Giant Water- Bugs. 



Whoever has interested himself in the Insect life of an average pond has 

 certainly become acquainted with a number of interesting aquatic representatives 

 of the bug family.'* The boatman, the water-scorpion, the water-measurer, and 

 the water-crickets are the species that are most likely to have attracted attention. 



1 Sialis lutaria. " S. fuliginosa. ^ Corydalis. * Hcmi])tera 



Phnto by 



Head of Giant Water-Bug. 



[E. SIfp, F.L.S. 



In this photograph only the head and shoulders of the giant bug are shown, enlarged four 

 times. The large compound eyes will be seen, and between them is the base of the rostrum 

 or sucking beak, but the beak itself lies along the under side when not in use. The 

 strangely-formed antennae are hidden in special pockets on the under side of the head. 



