362 INSECTS OF SUBFAMILY ENCYRTINZ—HOWARD. 
antenne, but may later be restricted to Tetracnemus, Tetracladia, Cal- 
ocerinus, and allied forms. 
The host relations of these insects may prove as variable as their 
structure. As yet we know with certainty the habits of but one—Pen- 
tacnemus bucculatricis—which was reared in large numbers from the 
overwintered cocoons of Bucculatrix thujella Pack., which had been 
sent to Dr. Riley from Cadet, Washington County, Mo., by Mr. J. G. 
Barlow. All of the specimens of Tanaostigma coursetie were extracted 
from the swollen ovaries of dry herbarium specimens of Willardia mex- 
icana, a rare legimunous plant, which was supposed to belong to the 
genus Coursetia at the time the description was drawn up, but which 
was subsequently made the type of the new genus Willardia. The 
most careful dissection shows no trace of any insect other than the 
Tanaostigma, but as we can not but suppose that this insect is para- 
sitic, the swollen ovaries must have originally been damaged by some 
= i} 
other insect, perhaps by some small rhyneophorus beetle. The other i! 
five species were all captured, Tetracnemus diversicornis on oak, Tetra- | 
cladia texana by sweeping grass, and Calocerinus floridanus upon oak. 
ih 
Concerning Hexacladia smithit and Tetracladia gracilis we have no 
further information than that they were collected, the former at Cha- 
pada, Brazil, by Mr. H. H. Smith, and the latter at Jacksonville, Fla, | 
by Mr. Ashmead. | 
The genera may be separated by the following artificial key: 4 
Provisional tribe Tetracnemint. 
MALES. ; 
Antenne with four branches. i 
Mesoscutum with a transverse oblique impressed line. .....---.. Tanaostigma How. 
Mesoscutum normal. 
Scapule widely separated at tips; antennae 10-jointed......Tetracnemus Westw. 
Scapule meeting at tips; antenne 11-jointed. 
Sixth funicle-joint of the antennie more than twice as long as the other five 
together... 22205522. . cee lo Gace eee eee eee eee oe eee Calocerinus n. &. 
Sixth funicle-joint shorter than fifth. ...............-....---. Tetracladia n. g. 
AMibenniee awl bh sve LAN CHES, 2222.5 ede eee ete aie eee Pentacnemus n. g. 
Antenne with six branches)....2../.. .-sa)- cee 4s sen oka eae Hexacladia Ashm, 
FEMALES. 
Antennal scape with a leaf-like expansion below........-...-.-.--Zanaostigma How. 
Antennal scape subcylindrical. 
Antenne arising at cly peal margin: 2.2.2. .oesenens -eeeeeeaeee Pentacnemus n. g. 
Antenne arising from above clypeus..............--.---s---- Hexacladia Ashin. 
TETRACNEMUS Westwood. 
Westwood’s original description of this genus and its single species 
was published in Magazine of Natural History, 1837, Vol. 1, new series, 
pp. 257-259, under the title ““A new genus of British parasitic Hymen- 
optera,” and is here copied: 
“Genus quasi intermedium inter Hneyrtum et Hulophum. Corpus 
