LEPIDOPTERA. 231 



among the Sphinges. They are easily recognised, in the per- 

 fected or winged state, by their resemblance to bees, hornets, or 

 wasps, by their narrow wings, which are mostly transparent, and 

 by the tufts or brush at the end of the body, which they have the 

 power of spreading out like a fan at pleasure. They fly only in 

 the daytime, and frequently alight to bask in the sunshine. 

 Their habits, in the caterpillar state, are entirely different from 

 those of the other Sphinges ; the latter living exposed upon plants 

 whose leaves they devour, while the caterpillars of the ^gerians 

 are concealed within the stems or roots of plants, and derive their 

 nourishment from the wood and pith. Hence they are commonly 

 called borers, a name, however, which is equally applicable to the 

 larvae or young of many insects of other orders. The caterpillars 

 of the iEgerians are whitish, soft, and slightly downy. Like 

 those of other Sphinges they have sixteen feet, but they are des- 

 titute of a thorn or prominence on the last segment of the body. 

 When they have come to their full size, they enclose themselves 

 in oblong oval cocoons, mads of fragments of wood or bark 

 cemented by a gummy matter, and within these are transformed 

 to chrysalids. The latter are of a shining bay color, and the 

 edges of the abdominal segments are armed with transverse rows 

 of short teeth. By means of these little teeth, the chrysalis, just 

 before it is about to be transformed to a winged insect, works its 

 way out of the cocoon, and partly through the hole, in the stem or 

 root, which the caterpillar had previously made ; and the shell of 

 the chrysalis is left half emerging from the orifice, after the moth 

 has escaped from it. 



The ash-tree suffers very much from the attacks of borers of 

 this kind, which perforate the bark and sap-wood of the trunk 

 from the roots upwards, and are also found in all the branches of 

 any considerable size. The trees thus infested soon show symp- 

 toms of disease, in the death of the branches near the summit ; 

 and, when the insects become numerous, the trees no longer in- 

 crease in size and height, and premature decay and death ensue. 

 These borers assume the chrysalis form in the month of June, 

 and the chrysalids may be seen projecting half way from the round 

 holes in the bark of the tree in this and the following month, dur- 

 ing which time their final transformation is efiected, and they burst 



