AMILACAN MOSEOGOM (GOIDE - LEAFLETS 

to eight parts; the eyes are large and usually brightly colored when 
the insect is alive; the proboscis is sometimes as long as, or longer 
than, the body; the thorax and abdomen bear hairs but not bristles; 
each wing has two submarginal and five posterior cells; the anal cell 
is usually closed but not far before the border of the wing; the mar- 
ginal vein runs entirely around the wing. The larve are aquatic, 
or semi-aquatic, and predacious. They taper at both ends and each 
of the eleven segments into which the body is divided bears a circlet 
of small spines. The adults fly by day, usually being found in warm 
sunny places, though some prefer shady woods. Only the females 
bite; both sexes feed on the juices of plants and on similar substances. 
There are several hundred species recorded from North America. 
The only other biting Calypterate which we have in the North- 
east is Hematobia serrata, the ‘““Horn fly.” It is less than half the 
size of Stomoxys calcitrans and the palpi are nearly as long as the 
proboscis, while in Stomoxys they are much shorter than the proboscis. 
The genus Glossina includes the tsetse flies; it is found only in 
Africa at the present time, although it formerly occurred in America, 
as is proved by fossils unearthed in Colorado. The tsetse flies are 
as large as, or larger than, Musca domestica, the ordinary house fly; 
the waist is constricted; the wings are crossed when at rest; the fourth 
longitudinal vein bends before it meets the very oblique anterior 
transverse vein. Both sexes bite, usually by day, but also at night if 
the moon be bright. The larve almost complete their development 
within the body of their mother and are then laid at the roots of 
plants. The pupal stage lasts from six to eight weeks. Several 
species have been described and their habits carefully studied but, 
owing to the facts that the larve are carried by the female until nearly 
or quite full-grown and that the adults feed on the blood of other 
animals than man, control methods are difficult. 
Certain insects are not real transmitters of disease but are them- 
selves its inciting agents. There are, for instance, dipterous larve, 
‘maggots,’ which occur by accident or as a part of their normal life- 
history in the human body. Such an occurrence is cailed myiasis. 
The most important species in this connection is the “‘screw-worm, ” 
Chrysomyia macellaria. It is a blow fly which has been classed with 
the Muscide and also with the Sarcophagide. The adult fly is 
nearly, or quite, half an inch long; metallic green; with three longi- 
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