57 
Family 
MUSCID/E. 
The three British blood-sucking species belonging to this Family 
are all nearly allied to the Common House-fly {Musca domestica, Linn.), 
but derive an even greater interest from their close relationship to the 
African Tsetse-flies (Genus Glossina), one species of w hich, Glossina 
palpalis, Rob.-Desv., is now widely known as the disseminator of the 
parasite which is the cause of the dread disease called sleeping 
sickness. In the Muscidas, which, in the widest sense of the term are 
perhaps the largest of all the families of Diptera, the blood-sucking 
habit is highly exceptional and is confined to a very few genera 
and species, all of which in appearance present a general resemblance 
to the Common House-fly. In cases in which the blood-sucking habit 
occurs, it appears to be common to both sexes. 
Blood-sucking Muscidae, with the exception of the Tsetse-flies, 
breed in dung, depositing eggs from which are developed white 
maggots of the type of those of the Common Blow-fly {Calliphora 
erythrocephala, Mg.). According to Riley and Howard, Lyperosia 
irritans, Linn. (Heematobia serrata, Rob.-Desv.), (Plate 30, fig. 2), 
oviposits on fresh cow-dung, and its eggs are irregularly oval in shape, 
flattened on one side, and from 1*25 to 137 mm. in length, by 0*34 to 
041 mm. in width. The newly-hatched larvae descend into the dung, 
and eventually when full-grown attain a length of 7 mm. Pupation 
takes place in the ground beneath, at a depth of from half to three- 
quarters of an inch. The puparium is of the normal Muscid type, 
dark-brown in colour, barrel-shaped, and from 4 to 4*5 mm. in length 
by 2 to 2'5 mm. in width. Stomoxys calcitrans, Linn., breeds 
in horse-droppings, and its larvae are very similar to those of the 
Common House-fly, which also breeds in horse-dung. 
