158 MODERN CLASSIFICATION OF INSECTS. 
legs does not (as in the Haltice, &c.) indicate saltatorial powers: 
Chalcis, &c., not being able to leap, whilst many of the small species 
with simple legs leap well; but it is amongst those which have the 
large intermediate tibial spur that we meet with these powers best de- 
veloped, the Encyrti, &c., being able to leap to an extraordinary dis- 
tance. 
The sexes of many of these insects are distinguished by various 
singular modifications of structure, independent of the more slender 
form of the body, and of the antenne of the males: thus in the males 
of many Eurytome, &c., the joints of the antenne are nodose, and 
furnished above with long hairs: the females of Cratomus have the 
heads of a very large size, being much broader than the thorax ; Chei- 
ropachus Weséw. has the posterior femora of the males, and the an- 
terior of the females (fig. 77. 11.) thickened ; Cerocephala Westw. 
has the head of the male curiously tricornuted. In Mesopolobus 
Westw. the maxillary palpi of the males are furcate, the third joint 
being externally prolonged ; and the middle tibia have a small trian- 
gular lobe on the outside ; in Platymesopus Westw. the middle tibize 
of the males are dilated. The males of many Eulophi and other genera 
have beautifully branched antennz. In Dicladocerus Westw. (Fron- 
tispiece, vol. i. fig. 4.) and Eulophus dicladus (Say, Journ. Boston N. 
H. Soc. vol. vi. p. 273.) the antennee of the males are 2-branched; in 
Eulophus they are 3-branched ; in Tetracnemus Westw. they are 
4-branched ; in Pentacladia Westw. they are 5-branched ; in Chirocerus 
they are 7-branched; and in some male Thoracanthe, 9-branched. 
The maxillary palpi of the males of Pachylarthrus Westw. are ter- 
minated by a very large globular joint (fig. 77. 10.); and the Rev. A. 
Matthews has recently discovered several curious species in which 
both the maxillary and labial palpi are thus constructed. Some of the 
species of the Pteromalides and Encyrtides are apterous, which is 
also the case with the females of my genus Theocolax. A curious 
peculiarity exists in one at least of these apterous species, which has 
been noticed by no previous author, and of which I am not aware of 
any analogous case in the order, namely, Choreius ineptus Westw. (En- 
cyrtus i. Dalm.), which, although ordinarily found in an apterous state, 
was discovered by me in considerable numbers, in the hot autumn of 
1835, with wings. 
These insects, which are generally of the most splendid metallic 
colours, and of which the majority do not exceed a line or two in 
