THE HARLEQUIN FLY 



CHAPTER I 



OUTLINE OF LIFE-HISTORY ; RELATIONS OF 

 CHIRONOMUS TO OTHER DIPTERA 



Note. — When an author's name is followed by a date, tlie work cited 

 will he found in the bibliographical list at the end. 



The naturalist wlio searches the mud at the bottom of Habitat, 



food, move- 



a slow stream will oiten m.eet with crimson larvae, an ments. 

 inch or less in length, which when full-fed turn to pupae, 

 and shortly afterwards emerge as two-winged flies. These 

 larvae are popularly called hlood-2V07'ms. They feed 

 chiefly on dead leaves and other vegetable refuse. Micro- 

 scopic examination of the contents of the stomach reveals 

 a blackish mass of vegetable fragments, besides diatoms, 

 infusoria, eggs of other aquatic animals, and grains of 

 sand. The larvae usually hide themselves from view, and 

 in deep mud form nearly vertical tubes which open at the 

 surface. When captured, their chief anxiety is to bury 

 themselves in mud or vegetation. If a larva is placed in 

 a saucer with a few bits of dead leaves, it will gather 

 them about its body, weaving them together with viscid 

 threads passed out from its mouth, and in a quarter of 

 an hour it will be completely concealed by a rude sheath, 

 which is not easily distinguished from the similar objects 

 which lie around. If the remains of plants are not to be 

 had, it will weave together grains of sand or particles of 



