HYMENOPTERA. 315 
Mygnimia coylonica, Saiissiire, 1. c. p. 64; Ceylon; M. avicuhiSf Sauss. ibid., 
pi. 2, fig. 28, Java. 
Mygnimia mexicana, Oresson, 1. c. p. 143, Mexico ; M. panamensisy Cress. 
1. c. p. 160; Panama. 
Pepsis duhitatay Cresson, I, c. p. 144, Georgia. 
Pcpsis australis, Saiissure, 1. c. p. 65, pi. 3. fig. 42, Australia. 
Ceropales nigripcs, Cresson, I, c. p. 139, Dakota ; C. rohmsonii, Cress. 1. c. 
p. 140, fig. 16, Virginia. 
Trigonalys pulchellus, Cresson, Proc. Ent. Soc. Phil. vi. p. 361, Virginia; 
T. {Lycogaste}') costalis, Cresson, I c. p. 362, Massachusetts. 
CRABRONIDiE. 
Packard (Proc. Ent. Soc. Phil. vi. pp. 363-446) concludes his revision of 
the North American species of Crabronidse and Nyssonidse. This’ portion 
includes the Crabronine genera Thyreopus with 14 species (tabulated on 
p. 366), Plepharipus with 6 sp. (tabulated on p. 372), and Rhopalum with 
3 sp. ; and of the Pemphredonince, Stigmus with 4 species, Cemonus, Pemphre- 
don, and Diodontus with 1 species each, Passalcecus with 2 sp., Psen with 6 
sp. (tabulated on p. 308), and Mimesa with 10 sp. (tabulated on p. 404). 
Ills Nyssonidas include the subfamilies Trypoxyloninm, with the genus Try- 
poxylon, 7 sp. (tabulated p. 413) and 3 unknown to author ; Mellinin^, vfiih. 
genera Mellinus, 2 sp., and Alyson, 3 sp. ; Nyssonince, with genera Gorytes 
with 14 sp. (tabulated pp. 423-424) and 6 unknown to author, Oxyhelus 
with 8 sp. (tabulated p. 434), Nysson with 4 sp., Stizus with 3 sp., and 
Larra with 6 species (6 unknown to author). Many of the species are de- 
scribed as new, and will be noticed hereafter. 
Nysson, (Gerstacker (Abhandl. naturf. Gesellsch. in Halle, 
X. pp. 71-126) publishes a revision of the speeies of this genus, 
which he preludes with a critical history of the works of former 
authors who have written on this subject. He discusses the 
genera Synneurus and Brachystegus founded by Costa at the 
expense of the genus Nysson, and characterized by peculiarities 
in the venation of the wings, and the subgenus Faranysson se- 
parated by Guerin on the ground of the presence of strong 
spines on the hinder tibia3, and shows, by the investigation of 
various species, that the characters adduced by these authors for 
the establishment of their proposed new groups are insufficient 
for that purpose, some of them perhaps individual peculiarities. 
The total number of supposed species described by authors is 32 ,* 
but these are reduced by the suppression of synonyms to 16, to 
which Gerstacker now adds 7, raising the total number of species 
recognized by him to 23. In characterizing the genus, Ger- 
stacker calls particular attention (pp. 86, 87) to the presence of 
two rings in the trochanters of the first and second pairs of legs, 
this to a certain extent forming an exception to the accepted 
division of the Hymenoptera into Ditrocha nnd Monotrocha. 
He finds the same structure in other genera of Eossorial Hyme- 
noptera, namely, Gorytes, Hoplisus, Bembex, Stizus, Philanthus, 
Tryjyoxylon, Cemonus, and Oxyhelus ; in the last the structure is 
