The Dobson and its Family 



places filled with aquatic plants in the border of streams and 

 ponds. They clamber through fallen vegetation with great 

 agility, and push their way readily through sediment falle-n upon 

 the bottom. In an aquarium, and probably outside, the long tail 

 is intermittently lashed up and down. This causes a swirl in the 

 water, which is doubtless useful in bringing a fresh supply of 

 well-aerated water into contact with the lateral filaments. When 

 the larvae are full grown they burrow into the soil for several 

 inches and become pupae without making a cocoon. The adult 

 fly emerges after two or three weeks. 



The eggs of Chauliodes have been found by Needham in the 

 Adirondack region of New York to be very generally parasitized 

 by a very minute egg parasite, a chalcis fly, more than seventy 

 per cent, of the eggs being destroyed in this way. 



The most familiar American example of this group is the 

 so-called hellgrammite fly, some account of which is given in the 

 following paragraphs. 



Life History of the Dobson 



(Corydalis cotnuta TL..) 



This is one of the most striking and most curious of insects 

 which occur in North America. Its transformations were first de- 

 scribed in part by S. S. Haldeman in 1848. It is interesting to note 

 that at that time, although the insect was well known to most peo- 

 ple in the localities where it was found, Dr. Haldeman was never 

 able to discover that it had a vernacular name either in English 

 or German among the so-called Pennsylvania Dutch. Surely this 

 defect must have been speedily remedied, since the great four- 

 winged fly with its enormous jaws is now generally known as 

 the hellgrammite. while its great, strong, biting, wriggling 

 larvae are familiar to fishermen in many parts of the United 

 States as Dobsons, or crawlers. In fact, it is likely that not one 

 of our insects has so many vernacular names at the present time. 

 In 1889 Professor W. W. Bailey, of Brown University, collected 

 the names in use in Rhode Island alone for this insect, and 

 they are sufficiently interesting to be repeated. They are : 

 Dobsons, crawlers, amly, conniption bugs, clipper, water grampus, 



