On Braula caeca, Nitzsch, a. Dipterous Parasite of the Honey Bee. 43 
reticulations and peculiar notches at either end make the recognition of the 
eggs easy and certain. 
The Larva of Braula caeca. 
Having thus established the fact that the bee louse is oviparous and not 
pupiparous as is so often stated, an endeavour was next made to trace out 
its life-history. For some time no traces of the immature stages of the 
parasite could be found in the hives, but finally a neglected hive was found 
in which the lice were very numerous. This colony had evidently been 
queenless for some time and was very weak ; many laying workers were 
2 
Fig. 2. — Egg of Braula caeca, x 70. 
present, and these had given rise to large numbers of drones. Two of the 
drones from this hive were very badly infested with the parasites, one 
carrying no less than eighteen of them and the other twelve. Both of the 
drones were undersized and both had obviously emerged recently. 
A number of the drone larvae were removed from their cells and 
examined under the lens. In several cases one, and in a few cases two, 
small dipterous larvae were found lying side by side with the bee larvae. 
The largest of these dipterous larvae measured about 2 mm. in length 
(Fig. 3). The buccopharyngeal armature, the tracheal system and the 
sensory papillae of these larvae were exactly similar to those of the embryos 
found in the eggs of Braula caeca (cf. Figs. 2 and 3), hence there could be 
no doubt but that these were the larvae of the bee louse. The bucco- 
pharyngeal armature is of typical muscoidean form, with well-developed 
