of the ruins of former layers of cells, presents a scene of such apparent disorder that {58}many have declared that the bumble-bees do not know how to build. Although the species of _Bombus_ are not comparable with the hive-bee in respect of the perfection and intelligent nature of their work, yet they are very industrious Insects, and the construction of the dwelling-places of the subterranean species is said to be carried out in some cases with considerable skill, a dome of wax being formed as a sort of roof over the brood cells. Some work even at night. Fea has recorded the capture of a species in Upper Burmah working by moonlight, and the same industry may be observed in this country if there be sufficient heat as well as light. Godart, about 200 years ago, stated that a trumpeter-bee is kept in some nests to rouse the denizens to work in the morning: this has been treated as a fable by subsequent writers, but is confirmed in a circumstantial manner by Hoffer, who observed the performance in a nest of _B. ruderatus_ in his laboratory. On the trumpeter being taken away its office was the following morning filled by another individual The trumpeting was done as early as three or four o'clock in the morning, and it is by no means impossible that the earliness of the hour may have had something to do with the fact that for 200 years no one confirmed the old naturalist's observation. One of the most curious facts in connection with _Bombus_ is the excessive variation that many of the species display in the colour of the beautiful hair with which they are so abundantly provided. There is not only usually a difference between the sexes in this respect, but also extreme variation within the limits of the same sex, more especially in the case of the males and workers; there is also an astonishing difference in the size of individuals. These variations are carried to such an extent that it is almost impossible to discriminate all the varieties of a species by inspection of the superficial characters. The structures peculiar to the male, as well as the sting of the female, enable the species to be determined with tolerable certainty. Cholodkovsky,[32] on whose authority this statement as to the sting is made, has not examined it in the workers, so that we do not know whether it is as invariable in them as he states it to be in queens of the same species. According to Handlirsch,[33] each {59}species of _Bombus_ has the capacity of variation, and many of the varieties are found in one nest, that is, among the offspring of a single pair of the species, but many of the variations are restricted to certain localities. Some of the forms can be considered as actual ("fertige") species, intermediate forms not being found, and even the characters by which species are recognised being somewhat modified. As examples of this he mentions _Bombus silvarum_ and _B. arenicola_, _B. pratorum_ and _B. scrimshiranus_. In other cases, however, the varieties are not so