June, 1907.] American Species of Papirius. i6i 



However, MacGillvray in The Canadian Entomologist, Vol. 

 XXV, gives some further characters which are of value in separat- 

 ing Smynthums from Papirius. His characterization is as 

 follows: 



A. Terminal segment of antennae long, ringed; larger claw uninden- 

 tate; apical segment of spring simple. Smynthurus. 



B. Terminal segment of antennae short; with whorls of hairs; larger 

 claw bidentate; apical segment of spring serrate on the imder side. 



Papirius. 



Of the general characters of the family, Papirius possesses 

 most of them. The antennae are long and slender, and often 

 distinctly annulated; however these annulations have been the 

 source of not a little confusion of the genus with Smynthurus; 

 manv investigators failing to see the division between the third 

 and fourth segment. Still by careful examination there may 

 always be found a distinct line separating the two joints. 



The legs are generally long, the larger claw bearing two or 

 more teeth. The spring is very long, and well adapted for leap- 

 ing; the dentes and mucrones in most cases being serrated. 



The ventral sucker is highly developed, and on agitating the 

 insect it may be seen to throw out the long tactile filaments 

 from the sucker. 



The segments of the globular abdomen are fused; only the 

 terminal segment being distinct. Dorsal tubercles are present 

 in some species and also tenant hairs. The eyes are distinctly 

 black, with prominent ocelli. The head in all species is loosely 

 joined to the body. 



The one characteristic of Papiritis which distinguishes it from 

 Smynthurus and Dicyrtoma is the four-jointed antennae, with 

 the short terminal segment. Smynthurus has a four-jointed an- 

 tennae, but the fourth segment is long, while Dicyrtoma has an 

 eight jointed antennae. This character of the short terminal 

 segment in Papirius is marked enough to make it quite a distinct 

 genus. 



General Anatomy. 



The general plan of structure of this genus does not differ 

 materially from that of other insects, and with the exception of 

 the terminal joint of the antennae does not differ at all from the 

 type of the family. 



The Body, as in all Smynthuridae, is globular in shape, and 

 the abdomen consists of six segments, the average length of the 

 entire animal being about 1 mm. The shape of the body may 

 vary to oval as in novoeboraccnsis, or sub -triangular as in texensis, 

 while unicolor has a slightly reentering angle at the tenninal 

 segment. 



The Head, is about as long as broad, and joined loosely to 

 the body. On its upper surface are the black eyespots. These 



