646 
DlPTEUA. 
proboscis of Glossina, an African blood-sucking Muscid. In both sleeping- 
sickness and Surra the parasite is conveyed much in the same way as 
the malaria parasite is conveyed by mosquitos, but with this difference, 
that the parasites (‘ ‘ trypanosomes ”) of sleeping-sickness and surra do 
not, it has been thought, multiply in the body of the fly, but are simply 
carried in the insect’s proboscis. Kecent work on sleeping sickness tends 
to prove, however, that a developmental cycle is undergone by the 
parasites in the tsetse fly (Glossina). 
All the Indian blood-sucking Muscidce are similar to house-flies in 
size and general appearance, except that Lyperosia is a good deal 
smaller. The commonest species is Stomoxys calcitrans , Linn. (PL LXIX, 
fig. 3). S. indica is not uncommon, and two or three other species 
of Stomoxys may also occur. The two common species of Lyperosia (L. 
exigua , de Meij., and a smaller one L. minuta, Bezzi) are abundant in 
certain localities but are rarely seen in others. Hcematobia ( H . irri- 
tans and one or two other species) is less common. There remain two 
or three species belonging to new genera recently described,* which 
are interesting as including one fly which is intermediate between the 
above-mentioned species and the ordinary house-flies, especially in 
wing-venation and the structure of the proboscis, which are the points 
in which the biting Muscidce usually differ from the non-biting. For 
convenience of reference we have included a plate of rough drawings of 
the chief types of Indian blood-sucking insects, and division C on the 
plate shows the head and wing of Lyperosia, Stomoxys, Hcematobia, 
Pliilcematomyia, and Musca the house-fly. Examination of the plate 
will show that the first posterior cell is nearly closed in Musca and 
Pliilcematomyia but quite open in the others, while the proboscis, long in 
Lyperosia, Stomoxys, and Hcematobia, is in Pliilcematomyia more nearly 
equal in length to that of the house-fly, though it is very stout and 
strongly chitinized. It is noteworthy that in biting this chitinized por¬ 
tion is not as in Stomoxys inserted into the wound, but remains outside 
like the labium of Culicidce, the actual puncture being made by an 
inner eversible portion which is armed at the end with a ring of stout 
hooks. This eversible portion is roughly indicated in the illustration. 
* Pliilcematomyia vnsignis, Austen Ami. Mag. Nat. Hist. Mar. 1909, the only species 
known at present. Fairly common and widely distributed. BdeJolarynx sang t c 
Austen 1. c. the only species known. Not common. 
