58S Dr. D. Keilin en iJie 



3. Mlcrosporidia. — The aliuieiitary tube and tlie salivary 

 glands of the larvae are souietiraes invaded with a iiiicro- 

 sporidiau parasite, which will be dealt with separately. This 

 parasite destroys the epithelial cells of the organs, and 

 appears to kill the larvee before they succeed to pupate. 



4. JJelicosporidiujn pcD'asilicum, Keilin^ 19.21, represents a 

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

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

 is very pathogenic and destrv)ys a good number of Dasyhelea 

 larvte. 



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 Mermithidte. 



VIII. Hereditary Bacterian Symbiont of 

 Dasyhelea obscvra, Winnertz. 



All the larvse of Dasyhelea 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 fly. They are then transmitted to tlie 

 eggs, and the small larvae 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 

 liereditary bacterian symbiont will be given in a separate 

 paper. 



IX. References. 



Carter, H. F., Ingram, A., & Macfie, J. W. S (1920). " Observations 

 on the Ceratopo^^onine Midges of tlie Gold Coast, witli 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. 



GoETGnKBUER, M. (1914). "Contribution a I'etude des Uhironomides 

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

 229, pis. v.-vii. 



GuEBiN, F. E. (1833). '' Notice sur les Metamorphoses des ceratopogons 

 et description de deux especes nouvelles de ce genre, decouvertes 

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

 pp. 10o-167, pi. viii. 



