Ants from British Guiana, 369 



Ps. gracilis, F., ^ . 



British Guiana, 20. 4. 15. 



Tliis is a most variable species. Forel (Biol. Cent.-Amer., 

 Formicidaj) says it nests in lioUow stems, where the ^ ^ 

 rest one beinnd the other, and varies in colour from yellow 

 through red to black witii every imaginable pattern. 



Ps. eleganSj Sm.j ^ . 

 British Guiana, 21. 5. 15. 



Tribe PiieidolinIj Emery. 

 Pheidole fallax (s. str.), Mayr., % ^ . 



" This species is of fairly common occurrence in British 

 Guiana. Formicarium constructed beneath the soil.'' 



Tribe Ceematogastrini, For. 

 Crematogaster stoUi, For., var. guianensis, var. nov., ^ , 2 . 



h. 3*2-7 mm. 



These examples of this extremely polymorphic Cremato- 

 gaster differ from the typical form as follows : Head and 

 thorax a lighter chestnut-brown, with the gaster a much 

 darker brown ; the head much smoother, witli hardly any of 

 the irregular punctures so noticeable in Fovel's duplicates, 

 ocelli in ^ major distinct, the pro-mesonotuni with tiner and 

 more regular longiludnial stiiation ; the basal surface of 

 epinotum longitudinally striate fanwise (irregularly and 

 transversely striate in stolli), spines of epinotum rather 

 longer. In the ^ minor the sculpture is also finer and more 

 regular, and the striation on the epinotum similar to that in 

 the 1/. 



This variety does not appear to be the var. amazonensis^ 

 For. 3 from the Amazon and also Costa Kica, as the description 

 only refers to tbe colour and spines, and makes no mention 

 of the sculpture. 



Tribe Solenopsidini, For. 



Subtribe Monomoeiini, Eur. 



Monumoriumjloricola, Jevd., S, ?, $. 



"In coconut/' Botanic Gardens, Georgetown, 7.4. 14. 

 A cosmopolitan species. 



