INSECTS AND DISEASE 
tudinal dark stripes on the thorax; its head is reddish to yellowish 
brown; its wing venation is similar to that of J/usca domestica. 
Several hundred eggs (sometimes the eggs hatch before they are laid 
and then living larvae are deposited) are placed on carrion or in 
wounds or sores in living animals. In the case of man, the eggs are 
usually laid in the nostrils of those suffering from nasal catarrh. 
The yellowish-white larva has rings of bristle-like structures on the 
segments, which give it the appearance of a screw. If it is not re- 
moved from the nostril, it may work in, causing an abscess and even 
death. Blow flies of the genus Calliphora (Muscide with metallic 
colored abdomen but dull colored thorax; fourth longitudinal vein 
sharply bent; distal third of antennal bristle bearing some hairs; 
cheeks unicolorous) sometimes lay their eggs on cold meat, espec- 
ially pork, and the larvz are then taken into the stomachs of careless 
eaters. Usually not much harm is done. The same is true of 
Lucilia (see page 10). The CEstride are closely related] to the 
Muscidz but the adults have rudimentary mouth-parts. They are 
the bot flies, and certain species do great damage to stock. In trop- 
ical America human beings are parasitized by the CEstrid Dermatobia 
hominis, and possibly other species. The larve live underneath the 
skin of various parts of the body. William B. Herms, in his useful 
Medical and Veterinary Entomology (Macmillan Medical Co., New 
York), gives a key to the larve ordinarily involved in myiasis. 
