SOME PARASITES OF SIMULIUM LARY.V. 321 



that in almost every brook visited some of these conspicuously- 

 distorted individuals were to be found. On making micro^cop- 

 ical examinations I observed that the organism- taken from dif- 

 ferent localities varied very much in form and apparently 

 represented different species. A list of these different form- and 

 the'r hosts is appended: 



1. Ovoid bodie- bearing a "flagellum "-like organ varying in 

 length from about that of the "body" to three lime- it- K-ngth 

 (Plate V., Fig. 14 . Ho-t : ShnnUinn hirtipcs. Habitat: Kotv-r 

 Hill- and Him- Hills, Mass. 



2. Bi-annulated ovoid bodie- bearim; a " Ma^ellum," which i- 

 rn-ver much longer than the "body" (Plate V., Kiu. 15). H<>-t : 

 Simtt/tttm species undescribed. Habitat: Stony Un>ok Reserva- 



t'on. Mass. 



.v <>\ ( )jd bodies ha\'ing the "flagellum" replaced by a trail 

 pan in flattened disc (Plate \'., Fig. !< Host: Sinndium 

 species undescribed. Habitat: Stony Brook K< - t \ ation. Ma--. 



4. simple o\oid bodies destitute of all appendage- Mate \ '.. 

 17). Ho-i : Simnlium species undcscriUd. Habitat : Stou\ 

 Bi I. l\- < : \ation and Blue Hills, Mass. 



Tht !.. Mowing characters were common to all of tin-. <>i-.m- 

 i - 1 11 - : 



1. Thr\ were all similar in size. 



2. I'mlrr i he highest power of the mi> ipe thc\ had a faint 

 oli\ i-h tinge. 



\\hcii in a IM -h condition absolutely n internal <li tail- \\ . 

 \i-iblc an<l in -| >n imens which had been killed, fivd and -tainrd 

 verj little more could be seen. In many of the first or "sperma- 

 to/oid" t\|>- a tlaikriied central area iudicati-d the presence 

 of a verj large iimlcii-, while a smaller dark -pot jn-t bcfi-rr the 

 ba-e of the lla'^flltini might be taken for the mieleulu-. 



Many of the " -i m pie ovoid " type, although but -lightly -tain- 

 ing, -Imueil a m'eat -hrinkage of the internal -ub-taiiee: oiher- 

 \\i-e nothing imiM be -een in them. The -peeimeii- \\ith a 

 flattened di-e. and ih.>-e bearing t\\o annuli and a lla^elluni, 

 al-n -ln>\\ed praetieallv no differentiation. Melh\l green and 

 \arioii- h.emato\\ lin i < -mbination- \\ere tried without success. 



He-idi - tlu-M- \ari(.u- fi irms, no two of which \\ire ob-cr\ed 



