158 Kmpnsa Miiscac rcrstfs ^Iiisca Domestica L. 



point of view, viz. the hibernation, the (juestion of resting spores, 

 so comnion i)i other species of this genus, and of artificial culture, — 

 still remain unsolved. But, while it is realised as possible that the 

 solution of these problems may have other than a scientific value, it 

 appears to me from my observation that we must look, for the control 

 of the fly problem, to other biological organisms — or remove systemati- 

 cally, by all necessary precautions, the insanitary conditions favourable 

 to the breeding of this annoying and dangerous pest. 



EXPLANATION OF PLATE XXI. 



Fig. 1. Empusa spore shot on vaseline at 'J. 15 a.m. 



Fig. 2. Same spore at 11.15 a.m. 



Fig. 3. „ „ 12.10 p.m. 



Fig. 4. „ „ 12.25 p.m. 



Figs. 5, G. Same spore, a little later. 



Fig. 7. Same spore at 4.40 p.m. 



Fig. 8. „ „ 5.20 p.m. 



Fig. 9. „ „ 5.30 p.m. 



Fig. 10. „ „ 6.5 p.m. 



Fig. 11. Spore shot on glass slide, mass of protoplasm drying up. 



Fig. 12. Same spore as before after 24 hours' germination. 



Figs. 13-17. "Involution forms." 



Figs. 18-20. Spore germinating into mother spore, and becoming separated from same. 



Fig. 21. Proboscis of Musca domestica and spore of Enipusa Muscac, relative sizes. 



