STATES OF INSECTS. 97 



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 a . 



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 b (Attacus Papliia) and other Bombyces, 

 which have orbicular depressed eggs with a central ca- 

 vity 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 sym- 

 metrical, as in those of a fly figured by Reaumur d : but 

 in general there is a correspondence in this respect be- 

 tween 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 striae, each distinguished by 

 a series of impressed points, which give it a beautiful ap- 

 pearance of net-work. In the others, as in a common 

 butterfly (Hipparchi a JEgeria) and moth (Geometra era- 

 tcsgata), the whole surface is covered with hexagonal re- 

 ticulations e . Others, as those of another butterfly (Hip- 



* Reaum. iv. 381. t. xxvi./. 19, 20. 



b Roxburgh in Linn. Trans, vii. 34. 



c Some of the Noctuas have similar eggs, as N. Lappa. Sepp iv. 

 t. iii./. I.e. d Reaum. ubi supr.f. 22, 23. 



e Plate XX. Fig. 6. 8. 

 VOL. III. H 



