588 Dr. D. Keiliii on the 



3. Microsporidia. — The alimentary tube and tlie salivary- 

 glands of the larvse are sometimes invaded with a niiero- 

 sjjoridian parasite, which will be dealt with se[)arately. This 

 parasite destroys the epithelial cells of the organs, and 

 appears to kill the larvae before they succeed to pupate. 



4. Helicosporidium parasiticum, Keilin, 1921, represents a 

 completely new type of Protist which invades the fat-body, 

 nerve-ganglia, and body-cavity of tlie larvre. This parasite 

 is very pathogenic and destroys a good number of Dasyhelea 

 larvfe. 



5. The perivisceral fat-body of the larva on two occasions 

 showed the presence of a parasitic body resembling the 

 trophic stage of a gregarine. This parasite will be described 

 separately. 



Nematoda. 



6. In a few cases the larva of Dasyhelea contained a 

 female of a nematode worm lying in the body-cavity. This 

 nematode, of which I only know the females, seems to 

 belong to the family of Mermithidie. 



Vm. Hereditary Bacterian Symbiont of 

 Dasyhelea obscuba, Winnertz. 



All the larvfe of Bm^yhelea ohscura contain in their thorax 

 four large bodies completely filled with bacteria. These four 

 masses of bacteria grow with the larva and pass into the 

 pupa and the adult Hy. They are then transmitted to the 

 eggs, and the small larvie which hatch from the eggs already 

 show the four bodies with bacteria in the perivisceral cavity 

 of their thoracic segments. The complete account of this 

 hereditary bacterian symbiout will be given in a separate 

 paper. 



IX. References. 



Carteu, H. F., Ingham, A-, & Macfie, J. W. S (1920). " Observations 

 on the (Jeratopojioniue Midges of the Gold Coast,, with Descrip- 

 tions of new Species. — Parts I. -II." Ann. of Trop. Medic, and 

 Parasitology, vol. xiv. pp. 187-274, pis. iv.-vi. 



Edwards, F. W. (1921). MS. notes, see pp. of this paper. 



GoETGHF.BUER, M. (1914). " Contribution a I'etude des Chironouiides 

 de Belgique." Annales de Biologie Lacustre, vol. vii. pp. 165- 

 229, pis. v.-vii. 



Guf BIN, F. E, (1833). " Notice sur les Metamorplioses des ceratopogons 

 et description de deux especes nouveUes de ce genre, decouvertes 

 aux environs de Paris." Ann. Soc. Ent. Fr. vol. ii., see 

 pp. 10-5-167, pi. viii. 



