640 MR. A. D. MICHAEi, OiN THE [DeC. 1, 



The numbers of Aphidae, Coleoptera, and indeed of other insects 

 which are commonly found in Ants' nests are too well known to 

 require any reference by me ; but the observations on the presence 

 of Acari in a similar situation are, as far as I know, very few. Forel 

 in his great work ' Les Fourmis de la Suisse,' published in 1874, 

 speaking of Myrmecophilous insects (p. 424), says: — " Acarina appear 

 to enjoy a certain immunity ; they run about amongst the ants without 

 exciting their anger ; it is rare to see them attach themselves to the 

 bodies of their hosts or to those of the larvte or nymphs. I have 

 nevertheless observed the fact many tim.es, and as it is the mode of life 

 of most Acari we may probably consider it as general in this instance 

 also. Moreover, living in the nest the Acari do not risk anything in 

 releasing one ant, because they can find as many others as they wish." 

 This is, 1 believe, his only notice of the subject. It will be seen that 

 Forel does not say what Acari he is talking about, and they are 

 almost as various as the different groups of the Insecta ; he also 

 falls into the very general, but by no means correct, view of sup- 

 posing that the great bulk of the Acarina are parasitic, whereas in 

 fact probably not half the species are ever parasitic, and amongst 

 those that sometimes are so by far the larger proportion are only 

 parasitic in an immature stage, not when adult ; and among these a 

 very large number only use their host as a means of conveyance, and 

 are not parasitic in any other sense. 



The first notice, which I am aware of, specially connecting any 

 Gamasids with Ants is thatof Hallerin 1877\ who describes a species 

 which he makes the type of a new genus and which he received from 

 Dr. Uhlmann, who found it, apparently near Munich, parasitic upon 

 (auf) Formica nigra. Haller does not state, and probably did not 

 know, the extent of the parasitism ; he had a dozen specimens. At the 

 end of his description Haller says " Parasitic upon Insects, especially 

 Ants ;" he does not, however, give any reason why he believes it to be 

 parasitic on anything except Formica nigra. This remained the only 

 species of the genus until 1888, when Prof. Berlese described two 

 new species found by A. Balzan ^ One from Brazil, called " caput- 

 carali,'' in spite of its name, is not stated to have been found on 

 any insect; but is so. called because the whole mite is supposed to 

 resemble the head of a Carabus ; the other, viduus, was found upon a 

 Beetle of the genus Scarites. 



The next notice is that of Sir John Lubbock, who in 1881 found 

 a very curious Uropoda in the nests of Lasius fiavus ; he obtained 

 several specimens, and informed me that it was not uncommon in the 

 nest of that species of Ant. It was called Uropoda formicarice^ 



The only other record which I know of refers to one of the 

 species dealt with in this paper, which was unknown when I started 



^ " Aiitenophorus uhlmanni, ein neuer G-amaside," Archiv fiir Naturgesch. 

 Hft. xliii. p. 57, 



- " Acari Austro-Americani quos collegit Aloysius Balzan," Bull. Soc. Ent. 

 Ital. 1888. 



3 " Observations on Ants, Bees, and Wasps.— Part VIII.," Journ. Linn. Soc, 

 Zool. vol. XV. (1881) p. 386. 



