This seems to be a minute beetle, as pictured in Objects for the microscope, being a popular description of the most instructive and beautiful subjects for exhibition by Louisa Lane Clarke.
It’s quite lovely, though. This is a sample of a larger illustration. Nearby on the same page, you can see the beetle life size, not magnified by any diameters. According to the caption, beetles like this are common in spring.
The book itself is sort of wonderfully arbitrary, like a Borges quote from an ancient Chinese encyclopedia – it’s a list of somewhat random objects, all of which would possibly delight a curious child with a microscope. Scales of a clothes moth. Spicules of sponge. Common cheese mites (found in the dust of decayed cheese, did you know?).
Louisa Lane Clarke also wrote books about being a governess and being a country parson’s wife, which makes me think she had experience in introducing children to the joys of nature and the hidden beauty of all things great and small.