Pertinacity is one of the most curious features of the performance of musical Locustids. One would say they desire to distinguish themselves as much as possible. Harris says that _Cyrtophyllus concavus_ mounts on the uppermost twigs of trees and there performs its Katy-did-she-did in rivalry with others. He says even the female in this species gives forth a feeble noise. Scudder says that some of the Katydids sing both by day and night, but their day song differs from that of the night. "On a summer's day it is curious to observe these little creatures suddenly {321}changing from the day to the night song at the mere passing of a cloud, and returning to the old note when the sky is clear. By imitating the two songs in the daytime the grasshoppers can be made to respond to either at will; at night they have but one note." Although but little is known as to the habits of Locustidae, it is ascertained that they are less exclusively herbivorous in their food habits than the Acridiidae are; many seem to prefer a mixed diet. _Locusta viridissima_ will eat various leaves and fruits, besides small quantities of flesh. It has been recorded that a specimen in confinement mastered a humble-bee, extracted with its mandibles the honey-bag, and ate this dainty, leaving the other parts of the bee untouched. Many of the Locustidae are believed to be entirely carnivorous. Brunner considers a minority to be exclusively phytophagous. The species very rarely increase to large numbers; this, however, occurs sometimes with _Orphania denticauda_ and _Barbitistes yersini_ in Europe, and _Anabrus purpurascens_ in North America. We have already mentioned that the eggs of some species are deposited in parts of plants, and of others in the earth. The British _Meconema varium_ deposits its eggs in the galls of _Cynips_ in the autumn; these eggs do not hatch till the following spring. _Xiphidium ensiferum_ has somewhat similar habits in North America, the gall selected for the reception of the eggs being the scales formed by a species of _Cecidomyia_ on the leaves of willows. It has been ascertained that the development of the embryo in the last-named species is commenced in the autumn, but is suspended during the winter, being only completed in the following spring, eight or nine months afterwards. We owe to Wheeler[250] a memoir on the embryology of this Insect.