246 FORTT-FIRST UePORT ON THE StATB MusEUM. 



throughout, with no particular features by which the head can be 

 distinguished from the tail by the ordinary observer — indeed by 

 some writers the two have been confounded, even when studied 

 microscopically. Figure 51, from a paper by Dr. Leidy, in the 

 America?! Entomologist for May, 1870, presents enlargements under 

 a high power of the extremities of different species of Gordius, and 

 shows marked differences and well-defined specific characters therein. 

 The Gordiacaea are not rare, but are from time to time met vdth in 

 turning over damp soil, perhaps in a little knot of several individuals 

 twisted together (whence we may have the " Gordian knot "), in barrels 

 of water, in ditches, wagon-ruts, ponds, pools, drinking troughs, wells, 

 etc. They are sometimes discharged from water-pipes, as in the 

 instance of a Gordius of about six inches in length, which was brought 

 to me by a lady who had detected it in a glass of water drawn from 

 a faucet, by the slight tingling sensation which it produced upon her 

 lips as she was about to drink in the dark. 



A Common Parasite of Insects. 

 As a parasite, Gordius occurs in the bodies of insects of nearly all 

 the orders, as Hymenoptera, Lepidoptera, Coleoptera, Diptera and 

 Orthoptera. Of the latter order, it is often found in katydids, crickets, 

 cockroaches and grasshoppers — sometimes as many as five in a single 

 grasshopper. They are met with in their parasitic stage by dissect- 

 tion of the insect, its accidental crushing, or in a voluntary escape 

 when the time has come for their free existence : they have frequently 

 been seen emerging from the heads of grasshoppers. 



Some of tlie Characteristics of Gordius. 

 The Gordius is a peculiarly constructed creature : microscopic 

 examination reveals what may be a mouth, but it seems to possess no 

 stomach, intestinal canal, or vent. Its interior is wholly occupied by 

 a white matter resembling the pith of a plant. . Its nutrition is sug- 

 gestive of that of the rootlets of plants ; yet it is known to have 

 generative organs, a nervous system, etc. It is wonderfully prolific. 

 It eggs have been seen to be extruded in a delicate thread or cord (as 

 at h in the figure) of an entire length of nearly eight feet, containing 

 as estimated from a small section, nearly seven millions of eggs. 



Its Iiife-History. 

 A brief summary of the life-history of the Gordius is as follows: 

 Its appearance while still in the egg, is shown at o, in Figure 51. 

 After emerging from the egg, it presents the successive appearances 

 given at p, q,. r, in Figure 52. In its earliest, or embryo stage, it lives 

 in water. Floating about until it comes in contact with some aquatic 



