328 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



sought for iu the proper places, as is the case with many other animals, the Hair-worm 

 is much less rare than is generally supposed. In the latter part of summer or the he- 

 ginning of autumn, in the search for the 

 animal, I have frequently found it, while 

 sauntering along the banks of a river or 

 creek, in little hollows close to the shore. 

 It requires some practice to discover it, as 

 usually it is comparatively quiet in such 

 situations, and may readily he confounded 

 with the blackened, decomposing vege- 

 table fibers occupying similar places. 

 Sometimes it is found single, and at 

 Fig. 65.— Hair-worms.— The young Variable Gor- others a number are discovered coiled 

 dius, after escaping from the e^g, highly magnified ; together in a loose but intricate-looking 

 p, the worm commencing to protrude the oral appa- ^ » 



ratus; q, the first circle of hooklets bordering the knotted mass. Such knots, which had 

 collar reflected, and the protrusion of the second cir- T^oj^opfl throno-h fhp watpr ninpa nnrl i<5«!nP<1 

 cle of booklets and the style ; r, complete protrusion P^^ea tnrougn ine water-pipes ana issuea 

 of both circles of the hooklets and style. (After at hydrants in our city, I have seen on 



two occasions. Similar knots, no doubt, 

 were the source of the scientific name of the worm, that of Gordius, applied to it by 

 Linnaeus, from the fabled Gordian knot of antiquity. The Gordius, however, not only 

 resembles the latter in the intricate condition into which it sometimes gets, but its 

 history is yet in part a Gordian knot to be unraveled. 



The worm is perhaps the hardest or most resistant to the feel of any of its order, and 

 it is tough and elastic. It is very tenacious of life, and when cut into several pieces 

 will continue to live and move for some time afterwards. 



Linnaeus accepted a popular error in regard to the Gordius. In his System of Nature 

 he says that, "if the worm is incautiously handled it will inflict a bite at the ends of 

 the fingers, and occasion the complaint called a whitlow." It is sufficient to refute 

 such a fancy when it is learned that the animal has neither jaws nor other instruments 

 by which it could either bite or sting. # * * 



Notwithstanding the simplicity of its outward form, its organization is of complex 

 character, and certain of its peculiarities are of special interest to the physiologist. 

 For jaws I suspect the forks of the tail of the male have been mistaken. Some Euro- 

 pean observers have failed to detect the mouth, though Dr. George Meissner, of Got- 

 tingen, a most accurate investigator, both describes and figures it. Sometimes, and 

 indeed generally, I have detected the appearance of a minute orifice, or pore, to one 

 side of the summit of the head in the Variable Gordius, but in other instances and in 

 other species, including the large Robust Gordius of Kansas, I could distinguish noth- 

 ing of the kind, the head end appearing as smooth as a watch-crystal, without the 

 slightest sign of even a depression. 



All reliable investigations, in addition to my own examinations, prove the total ab- 

 sence of anything like a stomach, intestinal canal. and vent, in Gordius. The interior 

 of the body is occupied by a soft, white matter, reminding one of the pith of sassafras 

 or other plant. This matter consists of polyhedral cells, resembling vegetable cellular 

 tissue, and forms a continuous mass from one end of the body to the other. Spaces in- 

 cluded in this cellular tissue are occupied by the genital and other organs. According 

 to Dr. Meissner, the mouth opens into a short gullet which expands upon the upper end 

 of the mass of cellular tissue. 



Nutritive liquid matter imbibed by the mouth, or the thin investment of the head 

 end of the animal, it is evident, can only pass throughout the body of the latter by 

 endosmosis from cell to cell of the interior cellular structure. The arrangement of 

 the latter, and the transmission of nutritive liquid, reminds one of the organization 

 and passage of liquids through the rootlets of a plant. 



Nothing like a system of blood-vessels, or nutritive tubes, nor like the tracheal air- 

 vessels of insects, can be detected in the structure of the worm. 



