Health Bulletin No. 31. The House-Freqenting Files Their Relation to Disease and Their Control

In most of the flies the eyes are closely approximated on the top of the head in males but are widely separated in the females. [...] It is in the larval stage that the whole of the growth takes place the entire life of the larva being devoted to the building up of tissues from which those of the adult are later derived. [...] The * The two sub-orders Orthorrhapha and Cyclorrhapha of the order Diptera are mainly distinguished by the manlier in which the adylt fly escapes from the pupal skin In the Cyclorrhapha the adult escapes through a circular slit. [...] The duration of the larval stage varies with the temperature and the quality of the food available. [...] Apiochmta scalaris.—This is a small fly of very variable colour markings It belongs to the acalypterate flies and can be easily distinguished from most of the other house-frequenting flies by the absence of squama covering the halteres and by the fact that the fourth longitudinal vein of the wing intead of bending upwards and ending near the tip of the third vein runs straight to the edge of