DAY-FLYING MOTHS. 185 



diurnal Lepidoptera fly by day, the habits of these 

 insects do not seem to prove a good basis for separation, 

 and in order to avoid the misconceptions produced by 

 the terms " diurna " and " nocturna," Boisduval, a French 

 entomologist, proposed to substitute Rhopalocera (club- 

 horns) for the butterflies, and Heterocera (different- 

 horns) for the moths. 



At first glance few distinctions appear more happy 

 than this few classifications more natural. It was no 

 sooner announced than it was recognized as a most 

 convenient arrangement, and quickly came into general 

 use. It is founded on the structure of the antennae, 

 often called feelers or horns, two long jointed organs 

 situated in front of the head, between the eyes, which 

 in this order are always conspicuous. A marked 

 thickening towards the end almost universally charac- 

 terizes the antennae of the Rhopalocera. Such being 

 the case, it is undoubtedly a character of primary 

 importance. But a certain family of moths (Sphingidae), 

 by their antennae thickening towards the end, though 

 terminating suddenly in a point, bring the two groups 

 into near relationship, and lessen their value ; while the 

 most interesting Castniidae and Uraniidae (of which more 

 anon) so intimately connect them that these families 

 have sorely perplexed systematists as to whether their 

 rightful position was with the one group or with the 

 other. 



