Are there any female characters in the Hobbit?

IIRC, the spider is female. I'm not referring to Shelob, the spider in Mordor - there's one in The Hobbit that attacks Bilbo and the dwarves in the woods.

A previous answer says that 3 female characters are mentioned in The Hobbit:

• Belladonna, Bilbo's mother
• The mother and Fili and Kili
• The wife of Girion of Dale

I can add :

• 2 sisters of Belladonna, as it is mentioned that she is one of three of the Old Took's daughters
• Gollum's grandmother. In the chapter Riddles in the Dark, "Gollum brought up memories of ages and ages and ages before, when he lived with his grandmother in a hole in a bank by a river"; and later, "Gollum remembered thieving from nests long ago, and sitting under the river bank teaching his grandmother, teaching his grandmother to suck - "Eggses!" he hissed."

There are also females referred to, in the plural:

• First chapter. We know that there are hobbit girls as well as boys "[Gandalf] had been away over The Hill and across The Water on business of his own since they were all small hobbit-boys and hobbit-girls."
• Smaug is said to devour inhabitants of Dale, especially young women. "Later he used to crawl out of the great gate and come by night to Dale, and carry away people, especially maidens, to eat, until Dale was ruined"
• Finally, when inhabitants of the city of the lake flee from the fire, "women and children" get into the boats.

So, though there are no female roles, we at least get to know that hobbits and men have daughters and wives. As for elves, there is no mention of females ever; and for dwarves, the sole mention of the mother of Fili and Kili is very short. Yet, it doesn't say that there aren't females elves and dwarves, it's just that they aren't specifically mentioned.

Quite often, we think that there are female characters in the hobbit, because they are in The Lord of the Rings, like female elves, female hobbits, and we mix the two stories in our memory. But in The Hobbit the terms stay in the gender-undetermined plural : the elves, the hobbits, the Sackville-Bagginses. As an example, in the last chapter, the Sackville-Bagginses are suspected of stealing the silver spoons but it's "they". No mention of Lobelia in The Hobbit; she appears only in The Lord of the Rings.

From: What are the Roles of Women in Tolkien? Middle-earth & J.R.R. Tolkien Blog (the author, Michael Martinez, is a Tolkien scholar known for very thorough digging through Tolkien material for analysis like this). Emphasis mine:

The Hobbit — There are no active female roles in The Hobbit. Published in 1937, this children’s story was essentially composed for J.R.R. Tolkien’s sons and although he expanded the original tale for publication he did not add any speaking female roles to the story. Nor did he add female characters in the two subsequent major revisions of the story that were published in 1950 (the Second Edition, which incorporated theoretical changes Tolkien had suggested to his publisher in 1947) and 1965 (the Third Edition, which was rushed into publication to address a copyright dispute). That said, there are three female characters who are mentioned in The Hobbit: Bilbo’s mother Belladonna Took, the unnamed mother of Fili and Kili, and the unnamed wife of Girion of Dale.

All three women serve a similar purpose in the story: their roles are to provide connections between major characters in the story and their predecessors. Through Belladonna Bilbo is connected to the Old Took, Gandalf’s friend; through their mother Fili and Kili are connected to Thorin, Thrain, and Thror; and through Girion’s wife Bard is connected to the ancient kings of Dale. These references to women in The Hobbit unfortunately set a precedent in the publication history that is hard for Tolkien to overcome.

As a side note, while the mother of Fili and Kili wasn't named in The Hobbit, she was named in LOTR, in Appendix A, part 3 (Durin's Folk):

Dís was the daughter of Thráin II. She is the only dwarf-woman named in these histories. It was said by Gimli that there are few dwarf-women, probably no more than a third of the whole people. They seldom walk abroad except at great need, They are in voice and appearance, and in garb if they must go on a journey, so like to the dwarf-men that the eyes and ears of other peoples cannot tell them apart. This has given rise to the foolish opinion among Men that there are no dwarf-women, and that the Dwarves 'grow out of stone'.

It is because of the fewness of women among them that the kind of the Dwarves increases slowly, and is in peril when they have no secure dwellings. For Dwarves take only one wife or husband each in their lives, and are jealous, as in all matters of their rights. The number of dwarf-men that marry is actually less than one-third. For not all the women take husbands: some desire none; some desire one that they cannot get, and so will have no other. As for the men, very many also do not desire marriage, being engrossed in their crafts.