Are there comprehensive species descriptions on most species? I was having a browse through Wikipedia and noticed how even the rarest, hardest to find species of bird have comprehensive articles and comprehensive descriptions, but other species like the 1400 _Andrena_ species have next-to-no information. I tried to do a search for resources on individual species of _Andrena_ bees but found very little - at best a short description and the name of the entomologist who described it. Is there a place I could go to find comprehensive resources on these bees? If not, why are the available resources on these species much less comprehensive than those on other species?

To suggest a new species, someone must necessarily makes a rather thorough effort of description. A good solution to get some info could be to go to the original paper however, these papers can be very old and hard to find. Also, the standards at that time might be very different from today's. After all, K. Linnaeus managed to describe 13,000 species also maybe because the description were more simple than they are today (see this related post). _Andrena hattorfiana_ was described by Fabricius in 1775 but I could not find the original paper.

Note that the english wikpedia article for _A. hattorfiana_ is relatively decent.

The IUCN red list is also a good source (see here)

The page for the Encyclopedia Of Life is unfortunately a little empty.

Here are some amazing pictures on flickr

You can also just search papers that refer to a given species. Here are a number of papers on _A. hattorfiana_.