SOME PARASITES OF SIMULIUM LARXVE. 



sexual organs entirely destroyed. Such individuals should be 

 capable of pupation and might in that way carry the disease over 

 as in the case of pebrine. An examination of several hundreds of 

 larvae did not reveal one in which such a condition was possible. 

 XVere there overlapping generations of larvae the maintenance 

 of the parasite could be more easily under-tood. but the spring 

 brood pupated and hatched during the first half of May. and 

 Him- an- noi at ilu- time of writing any signs of more eggs bein- 

 depo-it.-d on the rocks. It thus seems that there imi-t be a 

 ndary hosl in \\hich this parasite passes tin- summer. 1 



Tin-: PERCENTAGE OF INFESTED I.AKV i 



The number of infested larvae varied to a great -\tent in 

 ditlt ifin streams. In the part of the stream in Foiv-t Hills 

 \\li.-n- the para-ite-, were first noticed, les- than i per reni. of 

 the lar\.e \\ t <-iti/ed, half a mile further up the Mivam a 



little under 40 PIT cent, were infested, while in the Stony Brook 

 l\t -i-r\ aiion \\lnTi- two types of "spores" \\nv pn -nit among 

 tin- par s-iii/i-d larva', between 70 and 80 per cent, of ihe in- 

 di\idual- \\ere to be seen with the immensely di-ti-ndrd and 

 \\hiiened abdomens which proclaimed tln-m to be -nth 



11 ihi- I'at.il disease. 



h \\ill ilui> be seen that should this di^. Aether \\iih the 



previously di--i ribcd Mcrmis parasite, pro\e to .-\i-t a- abun- 

 daniK in other localities as it has during the pa-t -prinu in the 

 \itiiiii\ oi Bo-ion it must be of considerable im|)ortaiife in the 

 natural .ontrol of the black Hies which an- -neh an amioyaiiee 

 to man aiid bea-t, especially in more tn.pifal regions, and it' the 

 Mippo-i-d secondary host of the Sporoxoon doe-, not \>\-\ e to be a 



li-h or animal "t an\ \ alue it should be po>-ible to inter t -tr<-am> 

 \\lu-re simnliid lar\a- breed, and diminish their number- verj 

 lai.t-K \\itliout the danger of poisoning the li^h b\ apphin^ 

 oil or other MilMiires to the water. 



SUMMARY. 



.^iniidinni lar\a-. which are found in \ a>t number- in small 

 rapid streams around Boston, are seen to feed by standing per- 



1 I II.IM- >ino- July i\ imtiri-il isolated specimens of a different species of larva 

 in OIK- >>! tin- >tiMiii- u In n- tin- p.irasite abounded in the sjinng brood, but have 

 not tomi'l any in uhii.li tlu-ro \\ ^ of the para-itc In-iiiK present. 



