OF WASHINGTON. 221 



tubercles were never before made use of in systematic work, and 

 he felt sure these would be found to be of great taxonomic signifi 

 cance. 



- Mr. Banks presented the following paper : 



AN AMERICAN SPECIES OF THE GENUS CiECULUS. 

 By NATHAN BANKS. 



In every group of animals there are a few genera having char 

 acters which ally them to various larger groups, or serve to con 

 ceal their true relationship. In the Acari there are several such 

 genera, and not least interesting of them is CaBCulus. Its general 

 appearance at once reminds one of certain Oribatid mites, viz., 

 Nothrus. And on a closer examination one finds several struc 

 tures which would confirm this appearance. But there are cer 

 tain characters, deemed by acarologists of much importance, 

 which place the mite near a quite different family, the Trom- 

 bididas. These important characters are the palpi, the structure of 

 the coxae, and the peculiar eyes. The eyes are almost exactly as 

 in Trombidium, an arrangement not found elsewhere in the 

 Acari. But the dorsal shields, the rough spinose legs, and the 

 large ventral openings are characters wholly foreign to the 

 Trombididae. 



The early writers placed the genus after Oribata, and Gervais 

 suggests that it has some affinity with Phalangium. In 1877 

 Canestrini and Fanzago wrote a paper on the genus and erected 

 for it a new family, which they placed near the Trombididae. This 

 position it has since occupied in all classifications. Canestrini 

 and Fanzago gave the genus* a new name, Hoplopus ; because 

 they thought Caeculus inappropriate, and called the family Hop- 

 lopidas. But since Hoplopus is a synonym, the family should be 

 called Cajculidas. 



The genus is represented in southern Europe and northern 

 Africa by one species, C. echiuipes. Last spring Mr. H. G. 

 Hubbard sent me a mite taken at Palm Springs, California. It 

 proves to belong to Caeculus, and differs from the typical Euro 

 pean species in several minor particulars. 



Caeculus americanus, n. sp. 



Length 1.3 mm. Black, soft portions rather reddish-brown. Cephalic 

 shield more than twice as long as broad in front, twice as broad behind as in 

 front, sides sinuate, angles rounded; from the front margin there projects 

 four spatulate hairs or scales; there are two subparallel middle lines not 

 reaching to the hind margin ; under the hind angles arise a double 

 tubercle, each bearing an eye. Anterior shield of the abdomen one- 



