PACKARi-.J PARASITES OF THE LOCUST. 663 



Mr. Kiley, taken from G. sprcttis in Missouri. Regarding the frequency 

 of its occurrence in C. spretus, Mr. Whitman writes, under date of Sep- 

 tember 19, 1876: "I have opened six hundred and twenty- four hoppers 

 {spretus) ; nine of these contained grubs (of the Tachina fly probably) and 

 ten had hair-worms. I do not Isnow that the latter has ever been noticed 

 in hoppers in this State before this year ; at any rate, it has been so rarely 

 mentioned that I never heard of it here. I ought to say in regard to the 

 six hundred and twenty-four grasshoppers above mentioned that they 

 were probably some of a band of outsiders that have come into the State 

 within a few weeks. Almost every female had eggs about ready to be 

 laid." The specimen of Gordius received from Mr. Whitman was filled 

 with eggs. 



I will here give a resume of our entire knowledge of the hair-worm, 

 both because the worm is well known to the public, being sometimes 

 thought by the ignorant to be actually a transformed horse-hair, and 

 because it is prevalent in the bodies of grasshoppers, and has an ex- 

 tremely interesting history. 



The first notice of the hair-worm in this country by a naturalist is, so 

 far as I am aware, contained in " The Natural History of Vermont," by 

 Zadock Thompson. The following account is quoted at second-hand 

 from Charles Girard's " Historical Sketch of Gordiacew:^^ * 



The little animal called the Mir-sno.l-e also belongs to this order (Anmdata), and to 

 the genus Goi-diiis. These are very common in the still waters and mud in all parts of 

 the State. Tbey are usually about the size of a large horse-hair, and are from 1 to 6 

 or 8 inches in length. In color, they vary from pure white to nearly black, and hence 

 we probably have several species. The vulgar notion that they originate from hairs 

 which fall from horses and cattle and become animated in the water would seem to 

 be too absurd for contradiction, and yet, absurd as it is, people are to be found who 

 believe it. 



Mr. Girard adds : 



The same popular opinion is prevailing in Europe. (?or(Zu have been noticed in 

 the body of insects ; also, by an American entomologist. Dr. Th. William Harris, who 

 says, " I have taken three or four of these animals out of the body of a single locust." 

 They have been found by others within the cricket (Acheta abbreviata). 



We saw a specimen 6 or 7 inches in length caught iu the clear waters of the vicinity 

 of Richmond, Va. Several others were detected by Dr. Leidy in the neighborhood of 

 Philadelphia. Finally, we may mention several specimens of Gordii from Oregon, 

 brought home by the United States Exploring Expedition. Gordii, therefore, are 

 spread all over the Western Hemisphere. 



The mode of development of our common Gordius rarius (Plate LXIII, 

 rig. 6, h), has been studied by Dr. Leidy.t This is quite a different 

 species from Gordius aquaticus, the end of the body of the female being 

 trifurcated, while that of G. aquaticus is blunt. It is from 4 to 12 inches 

 in length, and appears to be much slenderer than Gordius aquaticus. 

 "The (ronZiMSvan'MS," says Leidy, "isprolific in a very remarkable degree." 

 A female 9 inches in length placed in a tumbler of water extruded a 

 string of ova 91 inches in length, in which he estimated there were over 

 0,000,000 eggs. Dr. Leidy saw the eggs undergo the process of seg- 

 mentation. On the third day, the germ appeared as an " oval, finely- 

 granular body," and by the teuth day the embryo was conical iu form, 

 with a cleft or fissure which extends two-thirds the length of the mass. 

 Upon the eleventh day it resembled a cylinder doubled upon itself, and 

 the tail-end was subacute. 



From the nineteenth to the twentieth day the embryo alternately retracted and pro- 

 truded the tentacular or filamentary appeudages, aud the integument of tho anterior 



*Proc. of the Academy of Natural Sciences, Philadelphia, v. ld5U and 1831, p. 27'J. 

 t Proc. of the Academy of Natural Sciences, Philadelphia, v. 9d aud '262, 1850 aud 1851. 



