4 Mr. T. D. A. Cockerell on Fossil Arthropods 
2, R.n. 1 nearly straight .........66. Stilpnus oligocenus, sp. 0. 
R. n. 1 strongly curved ..........4. Ichneumon acourti, sp. n. 
3. Stigma greatly elongated, not tri- 
gonal; ar. small .......seeseeee Coleocentrus gurnetensis, sp. 0. 
Stigma trigonal ........ seer eee eee é 
4, B. n. going far basad of t.-m.; 1.1 
BtTBISHb. Van ls wees os se an sinedeene Lithapechtis fumosus, sp. 0. 
B.n, meeting t.-m. or going slightly 
basad; r.1 curved .......sses05 5. 
5. A stump of a vein on r.n.1, repre- 
senting limit of disc. 1 .......... Itoplectis saxosus, sp. 0. 
No such stump of a vein ........-. Holomeristus vectensis, sp. n. 
6, T.-m. vertical, in line with lower part 
of b.n.; abdomen long-petiolate .. Cremastus arcuatus, sp. n. 
T.-m. oblique, or not in line with b.n. - 7. 
7, Radial nervure curved, not angled at 
t.-c.; b.n. meeting ti-m. 4....... 8. 
Radial nervure angled at t.-c. ...... 9. 
8. Marginal cell deep... .....-eeeeees Polysphincta atavina, sp. n. 
Marginal cell lanceolate .......... Lampronota disrupta, sp. n. 
Of Boneiryed = hse Wi. ck we ean Polyclistus anglicus, sp. n. 
B.n, nearly straight ..........++:: Acourtia perpleva, sp. 0. 
On comparing the Florissant (Miocene) Hymenoptera de- 
scribed by Brues (Bull. Mus. Comp. Zool.,1910) the following 
points of interest appear. TJrogus vetus runs in the above 
table to the Coleocentrus, which it rather closely resembles. 
Six species of Ichneumon figured by Brues all have the 
areolet more constricted above than J. acowrti. Hemiteles 
priscus runs in the table to Acourtia, which it resembles in 
the very oblique t.-m., but the shape of smd. is quite different. 
Cryptus delineatus has the areolet much like that of the 
Stilpnus, but otherwise differs. Protohellwigia, Brues, has 
no ally among our fossils. Hiatensor, Brues, runs in the 
table to Acourtia, but differs at once in the slender stigma 
and long narrow disc. 3. Evetustes inveteratus resembles 
Lithapechtis in many respects, but the stigma is much larger 
and disc. 3 shorter in the Florissant fossil. Mesochorus 
lapideus also resembles Lithapechtis, but the b.n. meets t.-m. 
The areolet is like that of several of the fossil species of 
Mesochorus. 
Slilpnus oligocenus, sp. un. (Fig. 1.) 
Thorax black. Anterior wing nearly 3 mm. long, pale 
ferruginous, with red-brown stigma and nervures ; st. large, 
m. deep, the radial nervure curved, not angled ; b. n. meeting 
the oblique t.-m., which is somewhat arched outward ; 
