138 TWENTY-TEIRD REPORT ON THE StATE CABINET. 



wliicli is invariably placed the lowest on the twig, are attached to the 

 bark by their sides ; in the next ring they are somewhat inclined ; those 

 of the succeeding rings, including the last, are placed on end, perpen- 

 dicularly, with their transverse diameter at right angles with the twig. 

 A quincuncial order of arrangement is readily traceable, i, e., any one 

 of the interior eggs is central to four others, of which two are in the 

 ring above and two below ; to these it is cemented at points midway 

 to the apices of the lesser and greater conjugates. When the regularity 

 of deposit has been interrupted, the quincuncial order is not maintained ; 

 but, through the crowding together of the members of a ring, the 

 assumed central egg may be united to one or two of the lateral ones, 

 thus giving it five or six points of union with those surrounding it. 

 From the above-described arrangement, it follows that an extension 

 over all the rings, of the lines joining the eggs of one ring to those of 

 another, will give us a succession of spiral bands crossing the stem at 

 an angle approaching 45°, and making about one circuit around it. 

 The belt is entirely free from any covering of down or other protecting 

 material. 



Egg Cement. — The eggs are firmly united to one another and to the 

 twig by a glutinous matter,* in which they are enveloped as they pass 

 from the oviduct. When, by the drying of the twig and its consequent 

 shrinkage, the belt is loosened and capable of being withdrawn, this 

 matter is seen as rings of a black substance surrounding the points of 

 attachment of the egg to the twig ; but around the points of union of 

 the eggs to one another it assumes a reddish color. 



For this difierence of color, no ready explanation presents itself. 

 Were its black hue owing to a thickening of the glutinous matter by 

 its gravitative flow down the egg while in a semi-fluid state, then upon 

 the lower side of a horizontal or inclined twig, it w^ould be found either 

 surrounding the points of union of the egg to the adjoining ones, or 

 collected at the apex. If it were a special secretion, deposited upon 

 the base of the egg on its expulsion from the oviduct, different from 

 that enveloping it, then it should not occur on the sides of the horizon- 

 tally-placed eggs of the first ring, as required by their exceptional 

 position. That it is not a chemical change resulting from contact with 

 the bark, appears from the fact that it assumes the same character in 

 the oviposition of several of the Bombycidne occurring in confinement 

 within paper, wooden and metallic boxes. 



* In many of the Lepidoptera this matter imparts to the eggs their color. Among 

 a hirge brood of Tclea Polyphemus (Linn.) reared by me, one individual, after having 

 been pinned and poisoned as were all the others, was found to have strewn her eggs 

 loosely about her; they were without the slightest degree of adhesiveness, and all 

 were of an abnormal uniform whitt^ color. 



