( cxcvi ) 



tropical Bee Aiithophora erubescens. In all these except the 

 Mutillids the ^ thorax is entirely black. The same phenome- 

 non is quite common in Sawflies (many Dolerus spp., some 

 Bleunocampids, Eriocampa ovata, etc.). I find no case of the 

 reverse, i. e. none where the ^ and not the 9 l^as the thorax 

 rufescent. 



Also, 071 the head, red is comparatively infrequent ; but where 

 it occurs, it is generally in the ? that I have noticed it — e. g. 

 many Ants, most of the large Scoliidae, Nectanehus fischeri, 

 several Cerceris spp., and the Bee Anthophora erubescens. 



Here, again, I can quote no instance of the contrary. It 

 would appear that, assuming such coloration to be Protective, 

 it is the 9 generally which receives the protection. However, 

 there are ^ (^ which enjoy it as icell as, or nearly as well as, their 

 females ; for a more or less red abdomen is usual in both sexes 

 of Sphecodes, and not uncommon in Andrena and Osmia ; it is 

 also frequent in both sexes of many Fossors, both among the 

 Pompilidae and the Spheyidae. 



I believe that in some cases these red colours are due to a 

 sort of immaturity, the insects which emerge before their pig- 

 mentation is fully develojied being redder than those which 

 have been more patient. In England Andrena hattorfiana 

 commonly emerges in the late summer and is quite black in 

 both sexes. But F. Smith noticed that in certain very hot and 

 early summers the 5 $ were apt, as on the Continent, to be red. 

 And in South Europe (Greece, Corfu, etc.) I have taken long 

 series of it in April in which all the $ $ and many of the ^ ^ 

 were red. Possibly a sudden heat-wave may bring the species 

 out abundantly at a time when some only of the c^,^ and none 

 of the $ 9 have coloured up properly. And this may conceiv- 

 ably apply to other cases of red-bodied, 9 $ occurring with black- 

 hodied ^^. Most of my own specimens above enumerated were 

 taken in hot spring-weather in Mediterranean districts. 



Now as to pictura albida. This, on the contrary, though it 

 occurs in both sexes, distinctly predominates (especially when 

 it occurs on the face and the front-parts of the body generally) 

 not in the $ $, as rufescence does, but in the ^ $. 



Thus it is almost universal in some genera of Bees and 

 frequent at least in others that the ^ face should be largely 



