STATES OF INSECTS. (Lge.) 97 
Ranatra have a similar use, as the female plunges them 
all but these bristles into the stems of aquatic plants? : 
but may not this have something to do with their oxy- 
genation? Reaumur has figured another egg of a dipte- 
rous insect which has a longitudinal wing or lateral 
margin attached to it, giving it the form of an oblong 
square, the object of which, he conceives, is to give a 
greater surface by which it may be more firmly fixed to 
the substance against which the fly attaches it. 
Besides these more striking variations in figure, their 
surface, though often smooth, is frequently curiously 
and most elegantly sculptured, a circumstance that di- 
stinguishes the eggs of no other oviparous animals. Some, 
as the margined egg just mentioned, are only sculptured 
on one side, the other being plain; or, as those of the 
Tusseh silk-worm © (Attacus Paphia) and other Bomby- 
cide, which have orbicular depressed eggs with a cen- 
tral cavity above and below, have their circumference 
crossed with wrinkles corresponding with the rings of the 
inclosed embryo“. Others again are sculptured all over. 
Of these, in some, the sculpture of the two sides is not 
symmetrical, as in those of a fly figured by Reaumur®: 
but in general there is a correspondence in this respect 
between the different parts of the egg. In those elegant 
ones before alluded to of some bird-louse attached to the 
golden pheasant, the shell resembles the purest wax, and 
is scored with longitudinal striz, each distinguished by 
a series of impressed points, which give it a beautiful ap- 
* Hist. Nat. gen. et partic. des Crust. et Ins, xii. 282. 
» Reaum. iv. 381. ¢. xxvi. f. 19, 20. 
© Roxburgh in Linn. Trans. vii. 34. 
* Some of the Noctue have similar eggs, as N. Lappa. Sepp iv. 
é. li. fi lee. © Reaum. wbi supr. f. 22, 23. 
VOL. ILI. H 
