PRESIDENTIAL ADDRESS. 



The Pteroptince — v;\\\c\\ are easily distinguished by their short, 

 thick, conical legs, the first pair of which are holding-organs— are 

 found upon bats. The bristles and hairs, with which they are 

 liberally provided, are jointed in a similar manner to the hairs of 

 the bats themselves. Dermanyssus avium is well known upon our 

 cage-birds, and is a frequent inhabiter of our poultry-houses. 



The second family, or IxodidcB^ contains the largest-known 

 representative of the order, the female of Ixodes ^gyptius attain- 

 ing the dimensions of one inch by three-quarters. Some speci- 

 mens from Rorke's Drift, in my possession, are fully seven-eighths 

 of an inch in length. Their rostrum is composed of two lateral 

 parts, or valvate palpi, sheathing the middle part, which is covered 

 with recurved barbs, which prevent its extraction when once 

 driven into the flesh. They may be met with in woods and 

 herbage, but more frequently upon animals, to which they have 

 attached themselves for the sake of a more liberal diet. From all 

 accounts, however, they appear able to endure long privation. 

 Some specimens of Ai-gas reflexiis^ sent me from Canterbury a 

 year or two ago, continued alive and active after being incarce- 

 rated some six months in an empty pill-box. 



The number of known English species is not large, but the 

 deficiency is fully made up in foreign countries, where some of 

 them have evil reputations on account of the poisonous nature of 

 their bite. The Argas Persieiis was figured in Eastwick's "Journal 

 of a Diplomato's Three Years' Residence in Persia," and he there 

 describes the novel cure prescribed at Meshed for its bite. A 

 servant of his underwent it. The patient goes to a house where 

 bowls of curds are served out to him. After having drunk the 

 contents, he sits down upon a seat suspended by ropes, which is 

 then spun violently round until it acquires the motion of a top. 

 The effect of this acting upon the curds is to produce vomiting to 

 such an extent that sea-sickness is a pastime to it. The patient 

 faints, but it is said most frequently recovers ! 



The Oribatidce constitute the next family, and as regards these 

 I cannot do better than refer you to the work before mentioned. 

 The investigation of their life-histories and the observation of 

 their habits will amply repay anyone devoting attention to them, 

 and there are some points in their economy that are still uncer- 



