3026 THE JOINTED ANIMALS 



recognized by the absence of the spurious vein in the wings, and also by their broad 

 heads, of which the fore part is produced into a conspicuous prominence bearing the 

 long antennae. L,ike the horseflies, the Conopidce in the adult stage frequent flowers, 

 but they lay their eggs in the bodies of various Hymenoptera, like bees and wasps, 

 and also in crickets and other Orthoptera. Here the eggs hatch and the larvae feed 

 upon the living tissues of their prey, and here they undergo their metamorphosis, 

 although they do not invariably quit the place of their development upon the death 

 of the victimized host. Taschenberg, for example, found the pupa of Conops 

 vittatus emerging from the abdomen of a humblebee which had been for six mouths 

 in his collection. The Conopidce are widely distributed, and especially abundant in 

 the Tropics. 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 which 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 toward 

 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 blowflies are well-known examples. 

 The characteristic structure of the wings may be seen by referring to the figure on 

 p. 3011. The proboscis is adapted for sucking, and usually ends with two fleshy 

 lobes. The flagellum of the antennas 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 blowflies, 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. 3030, and 10 in that on p. 3028). 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 (n in the figure on p. 3028). 

 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 without 

 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 windowpanes, 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; 



