Bees have the following characteristics

Bees differ from closely related groups such as wasps by having branched or plume-like setae (hairs), combs on the forelimbs for cleaning their antennae, small anatomical differences in limb structure, and the venation of the hind wings; and in females, by having the seventh dorsal abdominal plate divided into two half-plates.[25]

Bees have the following characteristics:

A pair of large compound eyes which cover much of the surface of the head. Between and above these are three small simple eyes (ocelli) which provide information on light intensity.
The antennae usually have 13 segments in males and 12 in females, and are geniculate, having an elbow joint part way along. They house large numbers of sense organs that can detect touch (mechanoreceptors), smell and taste; and small, hairlike mechanoreceptors that can detect air movement so as to “hear” sounds.
The mouthparts are adapted for both chewing and sucking by having both a pair of mandibles and a long proboscis for sucking up nectar.[26]
The thorax has three segments, each with a pair of robust legs, and a pair of membranous wings on the hind two segments. The front legs of corbiculate bees bear combs for cleaning the antennae, and in many species the hind legs bear pollen baskets, flattened sections with incurving hairs to secure the collected pollen. The wings are synchronised in flight, and the somewhat smaller hind wings connect to the forewings by a row of hooks along their margin which connect to a groove in the forewing.
The abdomen has nine segments, the hindermost three being modified into the sting.[26]

Head-on view of a male carpenter bee, showing antennae, three ocelli, compound eyes, and mouthparts
The largest species of bee is thought to be Wallace’s giant bee Megachile pluto, whose females can attain a length of 39 millimetres (1.54 in).[27] The smallest species may be dwarf stingless bees in the tribe Meliponini whose workers are less than 2 millimetres (0.08 in) in length.[28]