386 
HETEROMERA. 
central sheath is withdrawn and partly close the orifice; they vary very little in the 
species examined, and do not call for particular comment. 
The chitincus central sheath 
works freely in and out and is easily extracted entire; it varies considerably in structure 
in the different species, though to a less degree than the lateral lobes of the segment. 
These modifications of structure will be better understood from our figures; it is almost 
impossible to describe them satisfactorily *. 
The pectinate claws easily distinguish the Cistelide from the preceding and following 
groups. 
The following table, based solely upon species here enumerated, 
identification of the Central-American genera :— 
l. 
Penultimate joint of the tarsi (and sometimes the third or more of 
the basal joints of the two anterior pairs in the male) more or less 
lobed beneath ; intercoxal process of the abdomen (except in Menes) 
narrowly triangular. 
Penultimate joint of the tarsi not lobed beneath 
. Body winged . 
Body subapterous 
Body apterous 
. Anterior face of the prosternum more or less vertical, the head resting 
on this part in repose; eyes usually very large, at least in the male 
Anterior face of the prosternum with a gradual slope, the space in 
front of the anterior coxe broader . 
. Mandibles at most feebly cleft ; fifth ventral segment in male normal ; 
body not metallic. See ee ee ek ke 
Mandibles deeply cleft; fifth ventral segment in male abnormal; 
body metallic, hirsute 
transverse . . . . . - . soe ee ee 
Prothorax about as broad as the elytra at “the base, twice as broad 
as long . . 
Prothorax broader than the ‘elytra at “the base, the hind angles v very 
prominent and directed backwards . . . . .... 
. Prothorax not constricted behind . 
Prothorax constricted behind and subcordate in shape 
- Prothorax with a deep transverse basilar groove; body glabrous . 
Prothorax without transverse basilar groove ; body pubescent 
. Antenne very long and more or less filiform in both sexes . 
Antenne with the basal joint of usual length, the joints each a little 
widened towards their apex in both sexes . . 
Antenne with long basal joint, joints 4-6 dilated within i in the male. 
will assist in the 
Lobopoda. 
4. 
a B27 777 7) 2 
. Prothorax narrower than the elytra at the base, more or less 
ll. 
7. 
Telesicles. 
Charisius. 
8. 
9. 
Hymenorus. 
Theatetes. 
* Our figures have been drawn by Mr. G. S. Saunders, to whom we are much indebted for his assistance in 
the examination of these complex organs. 
