1880.] 51 



batch is the result, the number of the eggs in which is equal to the 

 sum of two successive ordinary batches of the same individual ; and 

 when, as already mentioned, a beetle is interrupted in the middle of a 

 batch, the next deposited eggs will be found to be the complement of 

 the batch so interrupted ; and if there has been any considerable in- 

 terval between these two portions, there will be a corresponding 

 interval between their times of hatching out, showing that the eggs 

 are only fertilized when they are about to be laid, or in their passage 

 from the ovaries to the ovipositor. The interval between two layings 

 varies in different individuals, and sometimes in the same individual ; 

 but the average may be stated at two days or somewhat less. Twenty, 

 thirty, or more than forty batches may be laid during the life of an 

 individual. 



As to the arrangement of the eggs upon the leaf, the first thing 

 to be noticed is that they are laid upon their sides, and not set 

 on end like the eggs of butterflies and those of the Colorado beetle, &c. 

 The typical arrangement seems to be in rows, to the axis of which the 

 long axis of the egg is inclined, at an angle somewhat under 90°. 

 These rows are commonly broken in the middle by an angle which 

 may have been originally determined by the furcation of the nerves of 

 the leaf. The ends of the eggs in each succeediDg row fit into the 

 intervals between the ends of the preceding one ; the last laid eggs, 

 however, are commonly less regular in their arrangement. The whole 

 batch has thus a somewhat fanlike or radiate appearance, and the apical 

 or caudal angle, when it can be made out, indicates the first-laid end 

 of the batch, and the direction in which all the tails of the future 

 larvae will be found lying ; the first-laid end of the egg always (or 

 nearly always*) being the caudal end. 



The individual egg is of a generally elliptical contour, about li — 

 1-| millimetres in length by half a mm. broad ; but there is commonly 

 a divergence from the perfectly elliptical form in two respects, im- 

 pressed upon the egg, as it would seem, in the act of oviposition. 

 During that pause of which mention has been made, after the first 

 half of the egg has been extruded, its long axis no longer corresponds 

 with the axis of the ovipositor, and a sort of curvature is impressed 

 upon it, giving the egg a subreniform or sausage shape, except that its 



* I have recently met with two apparent exceptions to this rule, both in the same batch, and 

 in a portion of it where the eggs were very regularly disposed. Two eggs, viz., one in the middle 

 of a row and one at the end of it, lay with their heads in the same direction as the tails of all the 

 rest. Now, if these eggs, lying orderly in line with the rest, were not laid head-first in place of 

 tail-first, the beetle, in laying them, and those immediately after them, must have executed a 

 very nice, difficult, and apparently useless manoeuvre in reversing her pcsition some three or four 

 times, so as to bring'the eggs into the exact situations they would have occupied if she had gone 

 on in the usual way. — J. A. O. 



