SECTIONAL TRANSACTIONS.—D. 425 
Treland—that the minute spinose maggots with powerful mouth-hooks, after 
hatching from the eggs laid on the host’s hairs, bore directly into the skin, and 
that the presence of second-stage maggots in the gullet wall of the host indi- 
cates a resting-place in the migrations of the larve to their final position beneath 
the skin of the back. The changes in structure undergone by the maggots— 
notably the reduction in the mouth armature through the successive stages, 
afford interesting examples in adaptation for specialised parasitic life relations. 
The presence of a series of six pairs of vestigial lateral spiracles in the fourth 
stage larva is a feature of morphological importance in connection with the 
degenerative modification shown by muscoid maggots generally. Attempts to 
exterminate these parasites in definite geographical areas show that the task is 
more difficult than has been hitherto supposed, as treatment for destroying the 
‘ripe’ maggots must be continued through a period of five months. 
19. Mr. F. Batrour BrownE.—Sapyga 5-punctata, a Fossorial Wasp 
Parasitic upon Bees. 
The relationship between the parasite and the Blue Osmia, O. cenea (cceru- 
lescens) was investigated and various experiments were made. It was found 
that larve hatched in the cells of the Red Osmia (0. rufa) never survived, but 
experiment showed that this was only because the pollen paste stored by the 
latter bee is drier than that stored by the Blue Osmia, and if this dry paste was 
moistened with treacle or honey the food was quite suitable for the Sapyga. 
Experiments in feeding the Sapyga larve, either on egg-food alone or upon 
pollen paste alone were inconclusive owing to scarcity of material, but they 
seemed to indicate that the egg of the bee was necessary as a preliminary to 
the pollen-paste diet. As to the origin of this case of parasitism, there are diffi- 
culties in the way of regarding it as a ‘ mutation,’ and it is suggested that the 
wasp originally oviposited in bee-cells containing full-grown larve, animal food 
being the normal diet of wasp larve; that in the course of time the wasp 
appeared earlier in the season—or the bee later—and the wasp larva completed 
its development on the pollen-paste diet, until now it only requires the egg of 
its host to enable it to pass through its first stage, after which the pollen paste 
supplies the necessary nourishment. 
The afternoon session was followed by a visit to Roslin Glen. 
Leader: Dr. Water RitcHis. 
Tuesday, September 13. 
20. Mr. T. A. SrepHENson.—Zoanthactiniaria: a Study in Classifica- 
tory Method. 
Among Actiniaria classificatory work must at present deal with genera and 
families, species being too little understood. A search for a satisfactory method 
of classification reveals that no system of unit-characters is reliable, the most 
adequate basis for work being the sum of the more important characters; this 
method resulting in a scheme representing relationships and evolution of whole 
animals and not of isolated aspects of their structure. Actiniaria may be traced 
from a small eight-rayed plankton-swimmer, the main evolutionary line divid- 
ing into anemones and corals and leaving curiosities behind it, the anemone 
branch, after shedding out further minority forms, itself dividing into two main 
lines of tendency. It is suggested that the mode of classification advocated for 
anemones might be applied to other animal groups, and that this might be a 
step in the direction of realising some fuller conception of classification, the 
need for such a conception being even now foreshadowed. 
21. Joint Meeting with Sections A, C, and K. Discussion on The 
Age of the Harth. See p. 413. 
22, Dr. Joun Renniz.—Acarine Disease in Hive Bees. 
The paper gives an account of the researches of Harvey, White, and Rennie. 
The term ‘ Isle of Wight Disease’ is now no longer possible as a designation 
for adult bee disease in this country, since it has been found to cover the 
1921 ome! 
