SOME PARASITES OF SIMULIUM LAKV.1 . 



domen. That thev -hould be present in the S'nnitlium e^> i- 

 hardly possible, and this hypothesis can be with safety rejected. 

 Either of the former hypotheses offers a po--ible explanation 

 for the variation in development "t" the histoblasts of para-iti/ed 

 larva- i.ikcn from different streams, for in the case ot those taken 

 ,n Norwood where the di-e- were of a moderate si/e. the worms 

 may not have entered the body cavity till the di-e- were -ome- 

 \\hat dc\ eloped Then ai^ain when- OIK- worm ha- -ro\\n to 

 nearly the normal -i/e of ^ cm. \\lu-rea- other \\orm- in tin- -aim- 

 hosl ha\e n-m. lined -mall, it i- probable that the lar^- \\orm 

 ciilcre<l the body cavity -onic time In-fore the other-. 



I- i;^ urc ( i, I Mate [V., which is a drawing of a median longitudinal 



ion of .1 p.u.i-ili/ed larva, >ho\\- the ventral position of the 

 \\orm \\itli re^anl to the aliment. iry tract, though it will 1 M- 



i that the me~eiitcroii lia- lieni -oineuhal pn-hed to i.iie -ide 

 l.\ the coiled parasite. It \\ill al-o In- -een 1>\ comp.irin^ I u. <i. 

 IM.ilt l\ '.. u ii h 1 ii-. I I , I Male I I I .. I hat tin- para-iti/e;l lar\ a ha- 

 much le-- fat IM, ( |\ than thai of a liealtlu individual a! aliotll 



the same rom th. 



Another e||. 'lie ho-t i- that apparently the -e\nal oi-an- 



do noi develop in paia-iti/ed l.n \ .e. The-c arc- n-.t easilj seen 



ill a lieallh\ Simi4 rva, as ihe\ are \er\ -mall, lull lhe\ 



can n-nallv lie found in . ies "I -eciion-; in sections <l 



|i.na-ili/ed l.n \ e I ha\e l.een eiitin-K imalile to locate them. 



< Mh ei u i-e the parasite appear- in ha\ e im el led on the internal 



in- ot the ho-.t. \\ith the excejition of di-]ilacin- the -pinning 



-land-, the I. ;iortion- < .1 \\hich normalK lie in the po-itimi 



later occiljiied \>\ the para-ite. Alt hotU'h the\ m.iy lie -o di-- 



plai'ed a- to lie d.ii-.ul of llie alimeiilaiA tract ' IMale 1\ . I 



their functioning - in no \\a\ impaired, since these larvae -pin 

 .mile as man\ -ilken threads as do those which are uninfested. 



The .\/<T;;//> prokiMy teed- <lirectl\- on the Mood pla-ma and 

 fat t\ ii ne of the ho-t. 



A- the lar\a reache- maturity the contained \\orm |.enne- 

 \er\- ri--tle--. and if a li\in- lar\a la- placed under tin- lo\\ pouer 

 of a micro-cope in a cell -lide the mo\emeiit- of th-- \\orm can he 

 ea-il\- ol>-cr\cd. I hie thn- \\atched lor aliout half an hour \\ a- 

 to explore the h\ |iodermi- of the ho-i , e\ idem 1\ atlemptin.u 



