4 Riley Presidential Address. 



social trait in the Lepidoptera is found in the small Hypono- 

 meutidae, and in a Mexican butterfly (Eucheira socialis Westw.) 

 the transformations taking place within the nest. The layers of 

 silk in the last-named species are so tough that they have been 

 used as parchment. 



In one remarkable case among the Diptera, viz., in Sciara, a 

 genus of small gnats, the larvae have the habit of banding 

 together in large masses, more or less elongate, all the individuals 

 attached to each other, heads to tails, and the whole mass moving 

 with one impulse and as a unit. They thus move across a road or 

 field, like some huge snake, and are for that reason called "snake- 

 worms," and really give us a very good illustration of . how indi 

 vidual units may combine to make a compound whole. Many 

 other insects have the exceptional habit of congregating together 

 in large masses, but in almost every case the congregating is con 

 nected with undue multiplication and the desire to migrate to 

 new regions. The habit is well exemplified in our notorious 

 Army Worm, the larvae of Leucania unipuncta, an insect which, 

 over vast stretches of country, occasions great loss to our grain 

 and grass crops by traveling from field to field and leaving 

 devastation in its wake. Instances of this kind might be multi 

 plied; but we do not apply the term social to such temporary 

 associations of individuals, even where they have any specific 

 purpose and are of annual recurrence. Nor do we apply the 

 term social to those insects, of which there are many in different 

 orders, which assemble together during the love or pairing 

 season. The term is strictly confined to those species which per 

 manently live together in colonies, and in which the social habit, 

 with its consequent subdivision of labor, and differentiation of 

 individuals, has become essential to their perpetuity. 



BEES. 



Living in such well organized communities, exhibiting so much 

 intelligence, and yielding one of the most delicious sweets known, 

 the Honey or Hive Bee has attracted attention from the earliest 

 times, and ever since Aristotle, Virgil and Columella told what 

 was then known of this industrious insect, it has been the sub 

 ject of investigation. Honey and wax were far more important 

 to man in olden time than they are to us who have so many sub 

 stitutes for them, and the ancients gave much attention of the 



