SPECIES IN ARTHROPODA 751 



there appeared to be every chance of its survival in the larvae of 0. nemo- 

 rosus, which were constantly present. It seems evident that infection 

 depends on certain conditions not at present known. 



Another form described by Kudo (19246) is Nosema anophelis, a 

 parasite of larvae and adults of A. quadrimaculatus. In the larvae it 

 occurred in the gastric pouch, and in the adults in the epithelial cells of 

 the anterior part of the mid-gut and in the neighbouring fat body. The 

 young forms, which reproduce by binary fission, are 1-5 microns in 

 diameter. Each pansporoblast produces a single spore, which measures 

 from 4-7 to 5-8 microns in length by 2-3 microns in breadth. The filament 

 is 50 to 60 microns in length. 



Marchoux, Salimbeni, and Simond (1903) described as N. stegomyiw 

 a parasite of the larvae and adults of A'edes argenteus (Stegomyia fasciata) 

 in Brazil. It occurs in the intestine, body cavity, and tissues of the 

 posterior part of the body, including the ovaries. It is supposed that 

 two kinds of spore are produced, the one colourless, the other brown. 

 The colourless spore gives rise to multinucleate plasmodia up to 40 microns 

 in diameter, and the brown spore to long filaments. There is considerable 

 doubt regarding the description of the parasite, the microsporidian nature 

 of which has not actually been demonstrated. Chatton (1911a) placed the 

 parasite in the genus PlistopJiora. 



Bresslau and Buschkiel (1919) recorded as Thelohania sp. a parasite 

 of larvaB of Theobaldia annulata in Germany. Noller (19206) mentions the 

 occurrence of a parasite which he supposes to be Thelohania legeri in 

 larvae of A'edes nemorosus in Germany. As T. legeri, according to Kudo 

 (1924), is specific for Anopheles, it is probably some other species. Ndller 

 also mentions Nosema sp. as occurring in A'edes nemorosus and A. cantans. 

 Bresslau and Buschkiel (1919) gave the name iVosema culicis to a parasite 

 of larvae of Culex pipiens. The spores measured 4-5 to 5-5 by 1*8 to 2-4 

 microns. What are possibly spores of Microsporidiida were seen by Pfeiffer 

 (1895) in larvae of Culex sp. in Germany, by Grassi (1900) in larvae and 

 adults of Anopheles sp. in Italy, and by Ross (1906) in adults of C . fatigans 

 and Aedes sp. in India. Kudo (1921), who has reviewed the literature 

 dealing with Microsporidiida of mosquitoes, doubts if these are, in most 

 cases at least, true Microsporidiida. 



SIMULIUM. — The larvae of various species of Simulium are very liable 

 to infection with Microsporidiida. Heavy infections occur, so that the 

 larvae often appear swollen and white in colour, while in some cases actual 

 nodular tumours are produced. The first form noted was one which 

 occurred in S. ornatuni, and was named Glugea variants by Leger, L. 

 (1897). The parasite was studied by Debaisieux (1919a), who found it 

 also in S. reptans. He transferred it to the genus Thelohania. It occurs 



