30 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVIII. 



■ '''I'h 



Fk;. 41. — Rhyxcholophis 



SIMPLEX .iXn PALPUS. 



Flii. 4o.— E'-.G OF 



Trombidium. 



trachea^ in this mite, and Thor believes that respiration is efi'ected 

 through the skin, the structure of which is rather peculiar. Upon 

 these differences he bases a family; however, in my opinion, this is 

 but more evid(Mice (if such is needed) of the uselessness of a classiti- 

 cation based on the respirator}^ sj'stem. 



In RhyncholophaH the mandibles onl}* are re- 

 tractile; there are but four eyes, and the palpi 

 are tive-jointed. We have many species of this 

 genus, and several of them are common and 

 wddely distribvited. The}^ are predaceous and 

 suck the juices from any small insect that they 

 are able to catch. One 

 species has been found 

 preying on the gloomy 

 scale {AsjndloUis teaeljr!- 

 c(>sus)'H.x\A others are found 

 feeding on the San Jose 

 scale and other scale in- 

 sects. In these situations 

 they are often the prey of 

 aphis-lions ( Chrysopa). 



Most of our species are 

 uniform red in color, but 

 7?. ctnctipes Banks has 



prettily banded legs, and fig. 4-2.-venter of sm.^ris. 

 i?. inacidatus Banks has 

 several large pale spots on the dorsum. One of our species, B. Jongi- 

 prs, has so extremel}' long legs that it resembles a minute Phalangid. 

 The genus EatonJana occurs in southern Europe and northern Africa; 

 it is remarkable on account of the plume of hairs on the hind legs. 



Family TKOMBIDIID.E. 



The •'harvest mites," as the}' are popularly called, are recognized 

 hx the body 1)eing divided into two portions, the anterior (cephalo- 

 thorax) bearing the two anterior pairs of legs, the palpi, 

 mouth-parts, and eyes; the posterior (abdomen) is much 

 larger and bears the two posterior pairs of legs. The 

 mandibles are chelate, at least there is a distinct jaw or 

 curved spine-like process. They also differ from the 

 allied Khyncholophida^ in that the last joint of leg IV 

 is not or very slightly shorter than the penultimate, and 

 in that the last joint of leg IV is not swollen. The last joint of leg I 

 usually is swollen, often more so than in the Rhyncholophida\ They 

 are always red in color, some, however, being much darker than others. 

 The body is covered with bristles or feathered hairs according to the 

 species. The palpi are tive-jointed, quite prominent, often swollen in 



