1852.] Ad 
these species were referred by me to the genus Pachylopus (vide Ann. Lyc. 
Nat. Hist. 5.) The epipleure of these last are marked with three strie. 
The spines on the tibie of S. dimidiatipennis are less numeroas than in the 
others, and form four tolerably distinct series. 
Synopsis of the Parnipm of the United States. 
By Joun L. Le Contr, M.D. 
As I have concluded, for reasons detailed below, to introduce the anomalous 
genus Eurypalpus into this family, I have found it necessary to substitute an en- 
tirely new diagnosis for the one given by Erichson.. The one proposed by me, 
in order to include the new genus, is as follows: 
Antenne frontales, non capitate ; oculi rotundati, mandibule retracte ; coxe 
antice vel subcylindricea, vel globose, acetabulis e prosterno et metathoracis ept- 
sternts compositis recepte; pedes ambulatorit, tarst S-articulati, cylindrict, 
unguiculart maximo, unguibus validis armato ; trochanteres simplices ; abdomen 
§—7-articulatum, articulis antertortibus immobilibus. 
The character which especially distinguishes this family is the structure of the 
tarsi, which enables the species to grasp firmly objects resting in strong currents 
of water. This family may be divided into three groups. 
Div. 1, Eurypalpini. 
Caput exsertum, ore inferno, labro distincto, inter antennas transverse eleva- 
tum; cox antice transverse, trochantino valde conspicuo; parapleure appen- 
diculate ; abdomen 7-articulatum. 
Evurypaueus| Dej. 
Antenne serrate 11-articulate ; palpi maxillares valde elongati, articulo ulti- 
mo latiore, securiformi, apice subacuto; labiales brevissimi, articulo ultimo 
minuto subulato. 
This very remarkable genus is mentioned by name in Dejean’s Catalogue, and 
is placed by that author towards the beginning of his group Malacodermata, near 
Cyphon, with which, however, it seems to have but little affinity. Erichson, 
probably never having seen the insect, referred it upon Dejean’s authority, to 
Cyphones, witha doubt. (Vide Agassiz Nom. Zool.) A close comparison with 
other groups has convinced me, that although its affinities in any direction are 
ape to discover, it must still be considered as forming a part of the present 
family. 
The body is depressed, narrowed in front, obtusely rounded behind. The 
mandibles are small, acute and entirely concealed by the broad and emarginate 
labrum; the mentum is trapezoidal; the ligula short, square and slightly emar- 
ginate at tip. The prosternum is truncate in front, prolonged behind into ar 
acute point which passes in a narrow groove extending the whole length of the 
mesosternum. The anterior coxe are precisely as in Helichus; the posterior 
coxe are slightly laminate and dilated interiorly as in Helichus, but are conti- 
guous at their base; the parapleure are broadly truncate at the external posterior 
angle, and the parallelogram is completed by a large triangular plate. The ab-. 
domen is 7-jointed, the first three joints are immovable, the 5th deeply emar- 
ginate, the 6th retracted so as to have only the edge visible, the last joint almost 
round; the fee* have the last joint much longer than the other four united, with 
strong simple claws. 
The larva resembles in appearance a ‘Trilobite, and has been described by 
De Kay as a Crustaceous animal under the name Fluvicola Herrickt. It is en- 
tirely aquatic, and breathes by means of branchial filaments, the principal ot 
which proceed from the anus. For a full description of it and the pupa see 
Agassiz’? Lake Superior. It bears a close comparison with the larva of Elmis by 
Erichson, (Deutschl. Insect. 525). i 
