some Bees from British Guiana. 4;'>7 



evidently palc-lialrcd as in Vaclial's species. In Friese's 

 table ours[)eeies runs exactly to exaltata, hut that has ferru- 

 ginous uervures, and the dorsal hair ot thorax is not l)]a(;k. 

 Nevertheless, the alHnity is close. The venation shows that 

 this cannot be the male of M. bod/cini. 



Megachile mutaticeps^ sj). ii. 



? . — Length 11 mm., anterior win«i^ 7'4. 



In Schrottky's table runs exactly to M. brethesi^ differing 

 by the dark teguhc, &c. It is extremely close to M. stoma- 

 tina^ Ckll., agreeing in most of its characters, but laigcr, 

 with the clypeus conspicuously different, as follows : — 



M. mutaticeps : clypeus shorter, densely rugoso-punctate 

 all over, with no smooth median space; lower margin 

 very broadly but shallowly excavated, the excavated 

 part undulate instead of erenulate ; disc of clypeus 

 with much long erect black hair, sides with creamy- 

 white hair (like that of sides of face), directed 

 downward. 



M. stomatara : clypeus longer, with a smooth and polished 

 median line ; lower margin not excavated, but 

 strongly erenulate ; disc without the long erect black 

 hair, and lateral pale hairs directed antero-mesad. 



The basal area of metathorax is entirely dull in mutati- 

 ceps, distinctly shining in both sexes of stomatura. 



The ventral scopa o{ mutaticeps is creamy-white, black on 

 last segment except basally. 



1 $ , Courantyne Coast, Berbice, Aug. 1915, constructing 

 nest in disused borings in timber (Bodkiji). 



This is a most interesting bee, clearly distiuct from 

 M. stomatara by the very different clypeus, yet found nesting 

 in the same manner, at the same time and place. 



Thus, so far as the evidence shows, we appear to have a 

 new species arising by mutation, without any change in the 

 mode of life or locality. 



While on South American Megachile, it may be worth 

 while to add a note on the two s})ccies, M. squalens and 

 M.susurrans, described by Haliday from Sao Paulo as early 

 as 1836. M. squalens is placed by Friese as one of the 

 indeterminate species, but tlie type is in the British Museum, 

 and there is a specimen at Oxford. M. susurrans is also in 

 l)oth these collections, 9 in the former, 4 in the latter. 

 Haliday described only the ? of susurrans, but at Oxford 

 I noted the male, with red tegului and tarsi much modilied. 

 Schrottky, in dealing with the Brazilian species (1913) was 



Ann. cD Mag. .V. Hist. Ser. 9. Vol. xi. 30 



