64 INSECTS. 



Bates gives an account of the habits of a species which he noticed hovering over 

 the armies of foraging ants. These ants, he says, "are accompanied by small 

 swarms of a kind of two- winged fly, the females of wdiich have a very long 

 ovipositor, and which belongs to the genus Stylogaster. These swarms hover with 

 rapidly vibrating wings, at a height of a foot or less from the soil over which the 

 ants are moving, and occasionally one of the flies darts with great quickness 

 towards the ground. I found that they were not occupied in transfixing ants . . . 

 but most probably in depositing their eggs in the soft bodies of insects which the 

 ants were driving away from their hiding-places, These eggs would hatch after 

 the ants had placed their booty in their hive as food for their young." 



The family Muscidce embraces a large and varied assortment 

 of species, of which house-flies and blow - flies are well - known 

 examples. The characteristic structure of the* wings may be seen by referring to 

 the figure on p. 48= The proboscis is adapted for sucking, and usually ends with 

 two fleshy lobes. The flagellum of the antennae is generally plumed with hairs on 

 both sides, though sometimes, as in the tsetse, the hairs are restricted to one side, 

 while in the spiny-flies it may be naked. The relative size of the three basal 

 segments of the antennae varies in different genera, but usually, as in the blow-flies, 

 the house-flies, and the tsetse, the third segment is at least three times the length 

 of the second (see b in figure on p. 69, and 10 in that on p. 65). It may also be 

 mentioned that the upper surface of the thorax is marked with a transverse suture, 

 and that the feet are furnished with a pair of adhesive pads (11 in the figure on p. 

 65). The family is divided into several subfamilies, and these may be grouped in 

 two sections, based upon the presence or absence behind the wings of a membranous 

 scale which, when present, covers the halteres or balancers. The subfamilies that 

 possess this scale are termed the calypterate Muscidce ; while those that are with- 

 out it are in contrast called the acalypterate Muscidce. Taking the calypterate 

 Muscidce, we begin with the subfamily Muscince, of which the house-fly (Musca 

 domestica) is the typical representative. This species may be found during 

 summer in numbers in every house, crawling up the window-panes, flying in 

 companies about the middle of the room, or creeping about the table in search of 

 food. It is the unwelcome companion of man in every country, following him in 

 .his travels, taking up its residence with him wherever he may choose to settle, and 

 resisting equally well the cold of northern latitudes and the heat of tropical climes. 

 For the most part, the eggs are laid and the larvae undergo their development in 

 excrement ; but the choice of the female does not seem to be always restricted to 

 matter of this sort, since she sometimes selects meal, bread, or fruit, for the 

 purpose. These flies are liable to the attacks of a parasitic fungus (Empusa 

 muscce) which causes their death, and in autumn it is not uncommon to find their 

 bodies killed by this means, with the abdomen much distended, and showing the 

 soft membrane between the segments. The common blue-bottle or blow-fly 

 (CalliphoTCi erythrocephala) is too well known to need description. One of the 

 most noteworthy features connected with this fly is the extraordinary keenness of 

 the sense perhaps smell, which enables it to discover the whereabouts of carcases, 

 however small, or of particles of meat. In these it hastens to lay its eggs ; and in a 

 longer or shorter time, according to temperature, the eggs hatch, and the larvae, 



