A. S. Hornk 111 



Indies the climatic conditions which favour the development of the 

 fungi would appear to be inimical to the insects, as in Dominica ; but 

 where and when dry conditions exist at certain times of the year, as at 

 St Kitts, few fungus enemies to insects are found. 



Some observations made in the case of CepJialosporium Lefroyi on 

 Aleurodes vaporariorum seem to be in agreement with the conclusions 

 of Morrill and Back. They are as follows : 



1. Dead imagos occur enclosed in a weft of Cephalosporium. 



2. Feeble but not always old imagos are not in every case associated 

 with Cephalosporium. 



3. Crushed feeble imagos have not always yielded hyphae and 

 spores. 



4. Feeble imagos may bear portions of the mycelium of the fungus. 



5. Dead, half-emerged imagos are often coloured orange and may 

 or may not be associated with Cephalosporium. 



6. There are large numbers of dead nymphs, some with Cephalo- 

 sporium, some with Cladosporium, others without fungi. 



We must carefully distinguish the case of the nymphal Aleurodes from 

 that of the imago. The nymph practically remains in situ on the leaf. 

 Fungi could live and grow on the honey-dew excretion caused by the 

 insect and ultimately invest the nymph and close the tracheae, a method 

 of action suggested by Giard 1 for Cladosporium parasiticum on Poly- 

 phylla fullo, and which may well happen in the case of the fungi under 

 discussion. 



Clearly the question of the parasitism of Cephalosporium Lefroyi 

 and the other species of fungi associated with Aleurodes vaporariorum 

 must remain open until the whole subject of fungi in relation to scale 

 insects has been reinvestigated by improved methods and put on a more 

 satisfactory basis. 



1 Giard in Comptes Rendu, cxii. 1518-21. 



