430 



NATURAL HISTORY OF ARTHROPODS. 



an inch. Not content with the ordinary habits of the blow-fly, they will deposit their 

 eggs in wounds of man and other animals, also at the openings of the human face. 

 Several fatal cases have been reported in this country caused by these larvae, to the 

 number of several hundred, growing within the nasal cavity. In South America cases 

 have been much more numerous. 



A very common and wide-spread species is the stable-fly, Stomoxys calcitrans. 

 They do not frequent our dwellings as do the house-flies, except before storms and 

 in the autumn, but the annoyance they cause horses and cattle is very great. They 

 resemble the common house-fly very much at first sight, but will be distinguished by 

 their holding the wings more spread apart when at rest, and more especially by the 

 proboscis being slender and firm, and directed forward. It is adapted for piercing, and 

 their food is chiefly the blood of vertebrate animals. The larvae live in fresh horse 

 manure. 



A more famous member of this group, allied to the last, is the Tsetze fly ( Glossina 



PIG. 541. Glossina morsitans, tsetze fly; a, head; b, antenna; enlarged. 



morsitans) of Africa, whose bite is so pernicious to horses and cattle as to render the 

 regions which they infest almost impassable for these animals. 



The Sarcophaginae differ from the Muscinae in the bristle of the antennas not being 

 feathered to its extremity. Many of the species resemble each other, and will be 

 recognized by the figure on page 429. The larvae live in excrements, decaying vege- 

 tables and fruits, or in flesh. Not infrequently the larvae, especially of Sarcophila, 

 have been known to infest the ears, nose, and wounds of man and other animals in 

 the manner of Compsomyia. The female deposits many thousands of eggs, or, what 

 is very frequently the case, living larvae, the eggs having been hatched before extru- 

 sion. Unlike the Muscinae, some few species have 

 been observed as parasites on the early stages of 

 beetles, moths, and grasshoppers. 



In the entire order, possibly in the entire class 

 of insects, there is no group so beneficial to man as 

 the Tachininae. The species are very numerous, and 

 in North America nearly wholly unnamed. They 

 are usually short, thick-set, bristly flies of small to 

 moderately large size, and will be distinguished from 

 the two preceding families by the bristle of the 

 antennae being wholly bare. They are sober-colored, rarely conspicuous, quick-flying 

 and abrupt in their movements, and frequent flowers and rank vegetation. 



FIG. 542. Tachina doryphorce. 



