100 MR. NEWPORT'S FURTHER OBSERVATIONS ON 



species is viviparous. The females, already fertile when they quit the cell, move at first 

 with great celerity, the abdomen being then the smallest portion of the body. But as 

 soon as they have penetrated into other bee-nests, and affixed themselves to the bodies of 

 the inmates, and begun to drain them of their fluids, the posterior three or four segments 

 of the bodies of the little nondescripts become rapidly more and more enlarged, and 

 assume the spherical bladder-like appearance seen on the bee-larva or its parasite. This 

 enlargement is carried to such an extent, that this portion of the body of the gravid 

 Acarus soon becomes at least ten, or twenty, or even more times its original size, and 

 at first sight seems alone to constitute the entire being (fig. 8). The Acarus in the 

 meantime loses its power of locomotion, and becomes affixed to one spot, or changes 

 its place so little, and so imperceptibly, as to appear to be immoveable. Gorged with 

 the nutriment imbibed, it sinks into a state of almost vegetative existence, and seems 

 to lose all the energy and power of motion it originally possessed ; strongly reminding 

 us of a similar degradation of animal function which the active little Meloe undergoes 

 before it attains its full growth as a larva ; and which the Stylops also passes through, 

 before it is re-developed in the one sex as one of the most lively of beings, or diverges 

 still further in the other, from the usual condition of an animal, as a mere nidus for 

 the production of new existences. This approach to the vegetative type is the form 

 in which these pregnant Acari are found in the bees' nest, crowding over, and hiding the 

 remains of the larva they have destroyed. From all which I have as yet been able to 

 observe, these Acari appear to become nidi for the development of the eggs formed within 

 them ; and I have much reason to believe that, as in Stylops, the young pass through their 

 earlier stages within the bodies of their parents, and escape from them in an active con- 

 dition, possibly at first as hexapods. The common cheese mite, according to Lyonnet, pro- 

 duces living young at some temperatures, and ova at other more reduced ones ; and this, 

 as we know, is the case with the whole tribe of Aphides among insects. Whether the 

 female Acari perish before their young are hatched, or whether, as I believe, the birth of 

 these is the immediate prelude to their parents' death, I have not yet ascertained. It is 

 certain, however, that the largest-sized females become discoloured earlier than the smaller, 

 and this too I believe in proportion to the temperature of the season. The temperature of the 

 season, or of the locality in which the Acari are placed, greatly influences, not only the 

 more or less rapid enlargement of the bodies of the females themselves, but, as I believe, 

 the hatching of the ova within them. This has been proved to me by the fact that a very 

 large proportion of the females, with the abdomen of full size, early in the autumn, but 

 when the temperature of the season was gradually subsiding, — and which I was careful 

 not to expose to the sun, — have remained alive during the winter to the present time, a 

 period of five months, without producing young, or, so far as I can discover, depositing 

 any eggs. In some of these specimens which I examined a few days ago, I found the 

 ova still immature, and even the germinal vesicles within them still present, and easily 

 detected. We may conclude, therefore, that a rather high temperature is required to 

 complete the development of the ova and produce the embryo. This high temperature is 

 always found during summer in the natural haunts of the Anthophora. The clay banks 

 in which these insects construct their cells become heated by exposure to the morning and 



