The Boatman. 



^^D 



get wet, for his body is covered with a very dehcate coating of fine down, which 

 imprisons a thin layer of air, and so keeps the water from actual contact. When 

 under water this iilm of air shines like silver. 



If the long hinder legs of the boatman are examined closely, thev will be seen 

 to be flattened and the inner edge fringed with hairs to make them more efficient 

 as paddles. But this adaptation to aquatic u-^es makes them useless on land. When, 

 however, the boatman wishes to leave his pond — perh.aps to iind another where 

 food is more plentiful or the com- 

 petition for it less severe — he has 

 only to spread his tightly packed 

 wings. On such occasions, too, he 

 will display his antenn^E, which 

 arc ordinarily kept hidden away in 

 little pockets belov.- the large com- 



j)ound eyes. Several other water- 

 bugs appear, as aquatic Insects, to 



have no antennae, but it is only 



apparently so ; they are packed 



away in these pockets because they 



are useless in the water and might 



get damaged. Surface bugs, like 



gerris, that do not submerge their 



heads, keep their antennae extended 



and in constant use. 



There is one other adaptation 



to its aquatic life that should be 



mentioned : its method of obtain- 

 ing air. Some pond Insects have 



an air-tube at the hinder extremit\ 



whose tip is kept out of water, 



and so a constant supjily of aii 



passes through it to the bod\ . 



Others have an air-reservoir undt i 



their wings, and make frequent 



excursions to the surface to re- 



1 • 1 •. , , ^, , Photo by] iJi.SUp,b'.L.S. 



plenish its contents. The boatman The Bo.^tm.\n Rowinc. 



.-/i.->^-^r- , », 4-1 f 'il, il i.' A vii'W of the boatman in the position iiiuallv a^^\lllu■li. back downwarfis on 



1( poses on tne SUlIaCe Wltn tne tip the water. The •■ stroke " beijins with the loiig hind-legs at risht angles with 



,^f \i-c^ l^;,,^! U ^1., ^ 1 i. i-1 • thobodv, and is continued with a steadv sweep until thev are ahnost parall-;!. 



OI its nmCl-DOCly exposed to the an-, Xhc bu? is here shown three times larger than the real size. 



and we might exjject to Iind that it drew the air into its body at 

 this point ; but it is not so, at h^ast not directly. Along the centre of 

 the under side there is a low ridge fringed on t^icli side by long hairs, 

 and a similar fringe runs along each margin of tlie bodw The principal 

 inlets to the internal air-tubes are on the fore-body, and the fringes of hair 

 described constitute two covered ways under which air can ]:)ass from the tip of 

 the hind-bod\- to the spiracles on the fore-body 



