This is the large blue-bottle fly of New Zealand and is found everywhere in great abundance. Its larva feeds on decaying flesh and is of a dirty yellow colour, measuring, when full-grown, about seven lines in length. The pupa is buried at a considerable depth in the ground, the larva having descended before changing. The duration of this, and in fact of all the stages of the insect, depends entirely upon the temperature, but the females invariably deposit eggs, even during the hottest weather, and are never ovo-viviparous like the next species, and several others of the genus.
Family Muscidæ.
Sarcophaga læmica (Plate [VII]., fig. 10).
Another extremely abundant species having a similar history to the last, but its powers of development are very much accelerated owing to the larva being positively born alive. The females hover over meat and other suitable substances, depositing a number of minute wriggling maggots thereon, not infrequently to the great disgust of some hungry individual, who perhaps is making his dinner off a mutton chop which the fly has selected as a home for her offspring. These larvæ are all produced from distinct ova, which hatch before being laid, as I have often proved, by removing them from the insect's abdomen, and watching the young larva emerge from a minute elliptical white egg, covered with a thin leathery skin. Every one who has travelled in New Zealand must have noticed that, in the wildest spots, these insects assemble in large numbers as soon as any meat is uncovered, thus not only showing their universal distribution throughout the country, but also that they possess a very keen sense of smell.
Two British species at least, allied to this genus, have been introduced into New Zealand, viz., Musca domestica and Musca cæsar. The former is probably a world-wide insect, every ship teeming with it, but the latter is at present rather scarce and is usually found in the neighbourhood of farm-yards, where the larva feeds on cow-dung. The perfect insect may be at once known by its brilliant green colour.
Family Muscidæ.
Cylindria sigma (Plate [VII]., fig. 14).
A curious species, occurring occasionally in damp situations in the forest where it may be noticed leisurely walking over the leaves of various shrubs. It is very sluggish and may often be captured between the fingers without the aid of a net. Its life-history is at present unknown, but the larva probably feeds on fungi. The pretty little insect depicted at Fig. 11 may be found in similar situations but is not so common.
Family Muscidæ.
Phora omnivora, n.s. (Plate [VII]., fig. 15, 15a pupa).