NOTES ON HYMENOPTERA. 85 



This parasite feeds alike on the larva and pupa of the 

 Anthojohora, and these, when attacked by it, have the ap- 

 pearance of being covered with minute semi-transparent 

 globules. I had frequently observed these previous to New- 

 port's discovery of their being living creatures : they are 

 extremely minute, and without the aid of a powerful micro- 

 scope their real nature would scarcely be detected. 



I may here record a very remarkable circumstance in 

 ^connexion with these Acari. Having kept several larvae, 

 attacked by them, in glass tubes for the purpose of observing 

 their progress, I found that the creatures never quitted their 

 victim; their proboscis, or sucking apparatus, being inserted 

 into the larvse at the time of their birth, and in this state 

 they imbibe its juices, arriving at their full growth, when 

 nothing is left of their victim except its thin epidermis. 

 When the Acari are fully matured, their bodies become so 

 distended, apparently with an incalculable number of eggs, 

 that it bursts open, and is then found to be filled with a 

 fine brown powder or impalpable dust, this dust being the 

 eggs of the Acarus. The following spring I obtained larvae 

 of Anthophora, as well as those of Osmia hicornis; these I 

 sprinkled with some of the dust, and in each case the para- 

 sites were shortly developed. 



Four years subsequent to this experiment, I found one of 

 the glass tubes containing the dust of the Acari, and had 

 the curiosity to try its effect upon fresh larvae ; I therefore 

 procured some, of several species of bees, and to my grati- 

 fication, with the same successful results. I am strongly 

 inclined to believe, that whenever the eggs of the Acarus 

 come in contact with suitable nourishment, their develop- 

 ment will follow, irrespective of lapse of time. 



These are a few of the causes that may tend to render old 

 bee colonies untenantable, and conduce to the emigration of 



