SOME PARASITES OF SIMULIUM LARV.E. 309 



maturation. In some cases, even, the rudimentary respiratory 

 filament histoblast begins to darken in color. 



I examined numerous specimens from the same Miv.im at 

 Forest Hills, and, with slight variations in intensity, they all 

 showed this nearly complete suppression of the imaginal di-c-. 

 Some weeks later I chanced to pass a small stream at Norwood, 

 about .-even miles from Forest Hills, and seeing Simulium lar\ ,e 

 pre-ent in small numbers, I took nine specimens from the rock- 

 in .nler to see whether the species w.t- identical with that common 

 in our >treams at Fore-l Hill-. They proved to belong to tin- 

 same specie-, namely, Simulium hirlipt-s, but I was much sur- 

 prised io find that hen- al-o ihe .l/,7/;;/x para-iu \\a- much in 

 evidence for o| tin- nine -pecinien- taken. -i\ contained the \\orm. 

 Tli' - |)O\M \erin th--i- -pecinien- were- not -. ; marked a- in 



tho-r found nearer home, lor tour of the -i\ had turned bn>\\ n 

 and althoii-h the hi-inbla-t- \\eiv much -mailer than is normally 

 the case ihe\ \\ r- readily visible to the naked eye. rndoubtedK , 



houe\er. malui.ition u.i- impo ible. t if even should the lar\ a 

 manage to |iii]iate it \\oiild -ooti ilie for \\aiil of oxygen, -illCC 

 the ie-piratorv hlanu nl- \\ere but half formed. 



In .1 third I'M.iliiv. the Slonx brook Reservation near Fop 



Hills, a different sp< larva was found. l'r: loh.mn-en 



-.t. Me- that thi- laiA.i i- quite neu to him and mav be the tin- 

 d( Drilled lar\al Stage of ':t:. uhich OCCtirs I Vei [iient ly 



in thi- . but as I found only adult- of hirtipt* it wa> im- 



p"--ible i i ill rm thi- supposition. The-e lar\ a- u ere. ho\\ e\ er, 



al-o f..imd t" -utter Inun .Ucr;;;/\ para-iti-m, but in a much 



le-- tAlellt than tll.>-eo| .S . /'..'. The el'lecl- nil tile ' 



were, however, as one \\mild expect, identic. il \\-it.i tho-e on 



hirtipcs, though the increa-ed -i/e \\.i- no) SO exideiit. 



A large number ol latx.e \\ere measured, cut 'p ( -n and the 

 \\ollll- remoxed. It i- ill tere-l i IIU here to Hole th. 1 e\-en ill 

 li\ed specimen- \\here tin- lluid had cati-ed the skin t" become 



opaque, the presence or absence of worm- eon'd in alJ ca-es be 



determined \\ith certaint\ by a .lance at the hi-toblanl -. The 

 \\onn. it should be noted, did not cause the abdomen to -well 

 up or Income di-torted to any appreciable <! 



A I. \\ -elected results -ho\\ n by the exam ina i ion are appended : 



