1959] 
Brown — Ant genus Str.umigenys 
45 
tect its position, freeze with mandibles held open toward it (at an 
angle of 6o°-70° in this case). However, sometimes workers ap- 
proach the prey and strike quickly and directly, without waiting. If 
prey is struck and continues to struggle, it is lifted off the ground 
and stung in the usual manner of Strumigenys. 
McCluskey and I found this species in nearly every berlesate of 
upper soil and leaf litter that we examined on Barro Colorado Island; 
it is evidently there the most common dacetine species and one of the 
more frequent ant species of the forest floor. Wilson found gundlachi 
to be somewhat less abundant in Veracruz. Although it is abundant 
in tropical rain forest, it also lives in second-growth forest, thickets, 
and cacao plantations. Weber (1952) took a sample deep in a cave 
on Trinidad among manure and debris from the oil-birds ( Steatornis ) 
and bats living there. 
Strumigenys jamaicensis Brown 
(Figure 4) 
Strumigenys jamaicensis Brown, 1959, Brev. Mus. Comp. Zook, 108: 6, work- 
er. Type loc.: Corn Puss Gap, 2000 ft., St. Thomas Parish, Jamaica. Holo- 
type in Coll. Illinois State Natural History Survey, Urbana, Illinois; 
paratypes in MCZ. 
Worker: TL 2. 3-2. 6 , HL 0.52-0.56, ML 0.40-0.42, WL 0.55-0.57 
mm. Cl 81-82, MI 75-77. 
Resembles S. gundlachi, but larger and with relatively much longer 
mandibles and antennae, particularly the scapes. Mandibles with 
gently convex outer borders and straight inner borders bearing 6-8 
strong, acute denticles which occupy about the distal 2/3 of the 
border. Body in general relatively more slender than in gundlachi. 
Sculpture, pilosity and spongiform appendages as in gundlachi, al- 
though in jamaicensis the ground pilosity tends to be less conspicuous 
and the erect hairs larger; also, the gastric hairs are larger and fewer. 
Color blackish-brown. Female and male unknown. 
In addition to the holotype nest series from Corn Puss Gap, I 
studied two additional (paratype) series from Hardwar Gap (about 
4000 feet), Portland Parish, Jamaica. All of the specimens were 
taken by H. B. Mills by Berlese funnel from soil-leaf litter charges. 
Distribution and relationships: So far as is known, this species is 
confined to the mountains of Jamaica. It appears to be a specialized 
descendant of an early immigrant population derived from the main- 
land gundlachi stock. Both gundlachi and eggersi now also occur on 
Jamaica, probably as a result of accidental introduction by man, but 
