The conditions under which this butterfly lives at the limit of its northern range are not well determined. It is probable that many of those seen here have flown from considerably farther south, and that these migrants lay eggs from which a brood of butterflies develops, these native born appearing late in summer. Presumably the latter hibernate, but whether they can do this successfully under the rigorous conditions of our northern winters has never been determined. In fact, Scudder wrote some years ago that no caterpillars had ever been found in New England. Here is an interesting opportunity for some young observer to make a real contribution to science. =The Little Sulphur= _Eurema lisa_ Were one to imagine a Clouded Sulphur butterfly reduced to half its usual size and built with a corresponding delicacy of structure, one would have a pretty good idea of the beautiful little creature called by the above name. I well remember in my college days taking what was probably the first of these butterflies ever collected in the region of our Michigan college. It was a prize that very likely had wandered north from Indiana but which served to add much glory to the little collection in which I took such pride, for this is essentially a southern species. In many regions of the South it is so abundant that it can be taken by any one. It ranges from coast to coast and extends south into the tropics. In the eastern region it is found from southern Wisconsin to southern New England, occurring sparingly and locally in various places along the line thus indicated. The food plant of the species is chiefly wild senna or other kinds of Cassia. The mother butterflies deposit the eggs singly on leaves or stems, generally on the small leaflets of the compound leaf. Less than a week later each egg hatches into a cylindrical greenish caterpillar that feeds upon the leaflets in a characteristic fashion. Instead of devouring the blade from the margin inward it gnaws narrow strips between the smaller veins. When not feeding, the caterpillars protect themselves from observation by birds or other enemies by resting motionless along the stem of the leaflet or else along the midrib on the under side. As is well known the leaflets of Cassia, like other leguminous plants, close at night. It is probably on this account that these caterpillars feed chiefly by day. The general green color of the skin and the straight stripe along the side help to make this caterpillar very inconspicuous when it is at rest. When full grown the caterpillar reaches a length of three quarters of an inch. It now finds some bit of shelter on which it spins a bit of flat web and a silken loop to hold it in place as it becomes a chrysalis. It then changes and remains quiescent for ten days or more when it emerges as the dainty butterfly.