i8 94 .] THE BRITISH NATURALIST. 163 



allies have red bodies, the females aeneous bodies. Agrion tenellum, 

 at least, has two sorts of females, one of which has no red at the base 

 of abdomen. The males of Lestes pennipes have blue bodies, the 

 females have grey bodies. The females of Anax formosus, Cordulia 

 Curtisii, and a few others have much darker wings than the males. 



A more wonderful difference, though, is seen in the wings of the 

 genus Calopteryx, those of the male being of a most splendid 

 metallic blue, of the female a very pale light brown. The males of 

 Clocon dipterum have black bodies, the females red bodies. The females of 

 Clocon luteolum have red bodies ; the males are red at the thorax and 

 at the tip of the abdomen, the intervening space being filled up with a 

 most delicate white with very thin red base. Similar distinctions exist 

 in others of the Mayflies. 



In Hymenoptera we find distinctions in : — 



Anthophora retusa and pilipes, males of a fulvous brown, females 

 entirely clothed with black hairs. 



Andrena fulva, male with black abdomen, female with abdomen 

 clothed with bright fulvous hair. 



Distinctions exist in others of the genus Andrena : — ■ 



Methoca ichneumonida and Myrmosa melanocephala, males entirely 

 black, females black and red. 



Pompilus notatus, male with black abdomen with a red ring and red 

 legs, female with red abdomen and black legs. 



Pompilus exaltatus, male with plain, female with variegated wings. 



Pompilus hyalinatus, male with plain wings, black abdomen, and red 

 legs ; female with variegated wings, red abdomen, and black legs. 



Sirex juvencus, with a metallic red abdomen, female with metallic 

 blue abdomen. 



Sirex gigas, male with a reddish yellow abdomen, female with a pale 

 yellow abdomen banded in the middle with black. 



Lophyrus rufus, male with a black abdomen, female with a red 

 abdomen. 



Lophyrus pini, male with a black abdomen, female with a yellow 

 abdomen banded in the middle with black. 



Ichneumon sarcitorius, male with whitish yellow bands on the abdo- 

 men, female with red bands on the abdomen. They have been 

 described as different species under the names of sarcitorius and vagina- 

 torius. 



Similar differences exist in other species of the Ichneumonidae. 

 In Diptera we find distinctions in : — 



Sargus bipunctatus, male with a bronzy green abdomen, female with 



