Ni;i ROPTEBATBIOHOPTEBA HYDROPSY* IIIDK. 



_'. I'Ol.Yi 'i:\TK'( >ITS Curtis. 



This is an important "Toup of caddis-flies to the paleontologist, since 



nearl\- one-half of tin- many phry^anids described from tin- I'russiaii amber 

 belong to it, and it is inteiv.Min.Lr to tind that we have at l.-a-t one species in 

 our own rocks. The present distribution of the species is maiiilv in Kurope 

 and North America, when- lliey are niiinen ni>, with a few recorded from 

 Ceylon. The larva-, according to .Md.achlan, inhabit shallow, rapid streams, 

 and form, I'ictet Bays, no firm cases until about to change to pup.-e. In 

 speakini; of the abundance of this jrroup in the amber fauna Mci.achlan 

 savs: 'Insects referred to 1 'ol vcentropus in its broad sense seem to have 

 been verv common in the Tertiary period when amber was formed; their 

 habit of concealing themselves in the rre\ ices of the bark of trees probablv 

 caused their entanglement in tin; resin and subsequent fossilixation." 1 



POLYCENTKOPUS EXESUS. 



A delicate winged, sparsely clothed species with exceeding! v delicate 

 antennae. The body is i ..... lerately slight, the head small: ha>al joint of 

 antenna: very stout, Bubglobular, the remainder thread-like, reaching back 

 beyond the closed wiii^s, the joints three to four times longer than limad 

 and narrowly ringed with black at the incisures. Le^s jmorlv preserved in 

 most of the specimens, but only moderately slender, the tar-i rather den-elv 



spinons. NVini^s moderately slender, broadest at the anastomosis, the ape\ 

 rather liroadly rounded, tolerably clear, hut with heavily iut'uscated veins: 

 the discoidal is much longer than the median cellule, and the .-econd apical 

 cell is longer than the third and fourth, and of about eijiial length with the 

 lit'th; the anastomosis above the fifth fork lies in a curve siihparullel to the 

 apical margin. 



Len-th of body, 7 .V ' : of front win.tr, s '"" : width of same. L'.i; rani ; 

 length of antenna', 11 ...... ; of hind tibia of hind tar.-i, 3.5 



Florissant. Nine specimens, Nos. ilT, .",71, 3143, 7I_S 7 s 7.'i, '.'."> -I'.i, 



i. i-jni, 13529. 



