630 
DIPTERA. 
slender, with the posterior spiracles dark coloured and somewhat 
raised. 
The fly shown in fig. 415 has been reared from larvae found in the 
bark of Til ( Sesamum indicum ). 
Sepsim. 
Head round, proboscis and antennae usually short. Abdomen slender, 
narrow at the waist . Male genitalia prominent. Basals and anal 
cell distinct. Sub-costa present or absent . 
The majority of these small flies are easily recognised by their form 
and colour. They are yellowish, shining black or dark metallic purplish 
brown in hue, and the abdomen is thin at the waist, its extremity being 
considerably thicker and generally bent downwards (PI. LXVII, fig. 8). 
The wings often have a dark spot near the tip. The larvae jump like 
those of Trypetidce, by fixing their mouth-hooklets in two small notches 
at the tail-end and suddenly releasing them with a jerk, which may 
propel the animal for six or eight inches. They are scavengers, living in 
dung or other decaying matter, and the flies may commonly be found in 
abundance about these breeding-places ; they have a habit of raising and 
lowering their wings as they walk, in a way that conveys an impression 
of daintiness and affectation amusing to those who know their real 
tastes and habits. In Europe and America, where cheeses are popular 
and smoked or dried meat is often stored in large quantities, flies of the 
genus Piophila (whose larvae are known as 44 cheese-hoppers ”) often 
do very considerable damage to these articles of food. The larvae and 
puparium are of the usual Muscoid type, the larva smooth, thick, and 
blunt at the tail end, and tapering away to the head, the puparium 
roughly the size and shape of a small brownish grain of rice, its surface 
rather winkled. The whole life-history occupies about three weeks or 
rather less. 
The common Indian species mostly belong to the genus Sepsis 
(Brunetti, Ind. Mus. Records), and the flies are very common everywhere, 
though less so in the plains than in the hills. In any hill-station they 
can be found in very great abundance and would constitute a serious 
danger to the health of the inhabitants were they not fortunately 
essentially 4 4 out-door ’ 5 flies. If they were in the habit of settling on 
food in kitchens or elsewhere, their custom of walking about on fresh 
dung would be sure very often to result in infection of the food with 
