Mr. F. Smith on the Genus Eulema. 441 



The above characters are those of the type of the genus, 

 Eulema dimidiata. This genus can only be separated from 

 that of Eughssa by an examination of the oral organs. I have 

 failed to obsei-ve more than two joints in the labial palpi ; and 

 upon this circumstance alone have I kept it separated from 

 Euglossa. The characters given by St.-Fargeau are not 

 reliable ; and the difference which he alludes to in the neuration 

 of the wings has no existence ; in both genera the nem-ation 

 is the same. The labrum varies slightly in the species, being 

 sometimes square, sometimes slightly narrowed anteriorly ; 

 the males in both genera have the posterior tibiaj thickened, 

 being convex outwardly. The scutellum is sometimes flat, 

 sometimes a little convex ; it has frequently a fossulet at its 

 posterior margin, or a depression, the sides of which are 

 elevated so as to become bituberculate. 



The insects belonging to this genus, Mr. Bates informs us, 

 are solitary in their habits. In the second volume of the 

 ' Naturalist on the River Amazons ' he observes of Eulema 

 surinamensis : — " This species builds its solitary nest in 

 crevices of walls or trees ; but it closes up the chink with 

 fragments of dried leaves and sticks cemented together, instead 

 of clay. It visits the cajii-trees, and gathers wuth its hind 

 legs a small quantity of the gum which exudes from their 

 trunks ; to this it adds the other materials required from the 

 neighbouring bushes, and when laden flies off to its nest." 

 The dilated posterior tibiae, fringed at the sides, and thus 

 forming a basket (similar to that on the legs of the hive-bee), 

 has led to the supposition of the insects of this genus being 

 social; but direct observation proves the contrary. These 

 bees are furnished with two spines at the apex of the pos- 

 terior tibiffi, wdiich none of the permanently social genera pos- 

 sess. The genus Bombus, which is temporarily social, has 

 spines similar to the genera Eulema and Euglossa, and has 

 also the posterior tibia3 expanded and fringed at the sides in 

 the same manner as those genera. Thus we have a gradation 

 in structure, as well as in habit, from Eulema to Euglossa, 

 and thence on to Bombus and the genera Meli^ona, Trigona, 

 up to the genus Apis. 



1. Eulema dimidiata. 



Eulema dimidiata, St.-Faror. Ilym. ii. p. 12, cJ $ . 



Apis dimidiata, Fab. Ent oyst. ii. p. 316. 



Centris dimidiata. Fab. Syst. Piez. p. 354 ; Schomb. Faun. Flor. Brit. 



Guiana, p. ol9. 

 Euylossa dimidiata, Perty, Del. An. Art. p. 151, tab, xxviii. f. 14, J . 



Hab. Cayenne ; Para ; Rio de Janeiro ; Bahia ; St. Paulo ; 

 Chontales ; British Guiana. 



Ann. & Mag. N. Hist. Ser. 4. Vol.xm. 32 



