Note on the head the large _compound eyes_. Note the tumid convex _clypeus_ which composes most of the anterior aspect of the head. Are _ocelli_ present? Compare the _antennæ_ with those of the locust and water-beetle. Compare also the _mouth-parts_ and note that they differ radically from those of the locust and beetle. They are not fitted for biting, but for sucking up liquid food (the nectar of flowers). Note the absence of a movable flap-like _labrum_ (a minute narrow stiff piece, bearing at each latera end a small group of fine brown hairs, represents the labrum), the entire absence of _mandibles_, and the absence of a movable flap-like labium. The _labium_ is a fixed chitinized triangular piece forming part of the floor of the head. Note the long slender _proboscis_ coiled up like a watch-spring. (In fresh specimens this proboscis can be uncoiled and will be found flexible. If dried or alcoholic specimens are being studied, the head of the butterfly should be removed and softened in warm water before the mouth-parts are examined.) On either side of this proboscis is a peculiar pointed process which rises from the under side of the head. These processes are the _labial palpi_ and serve to protect the sucking proboscis. The proboscis itself is composed of the two greatly modified _maxillæ_. Instead of being short, jaw-like and composed of several pieces as in the locust, in the butterfly each maxilla is a slender, flexible half tube applied against its mate on the opposite side in such a way as to form a perfect tube long enough to reach into the nectaries of flowers when in use and capable of being compactly coiled up at other times. Cut across the proboscis and note the canal in the centre. Try to separate the two maxillæ which compose it. Make a drawing of the frontal aspect of the head with the eyes and appendages.