Dear Maarten van Helden

You may contact the researcher on the same project, they will help you and send the working identification key Pls. find the attached files

http://www.scielo.br/scielo.php?pid=S0085-56262013000300005&script=sci_arttext

https://www.researchgate.net/publication/226782686_Keys_for_Identification_of_Immature_Insects

http://www.tandfonline.com/doi/abs/10.1080/09670878409370850

http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1085&context=insectamundi

https://www.jstage.jst.go.jp/article/aez/37/4/37_4_595/_pdf

https://www.science.gov/topicpages/s/scarabaeidae+scarabaeinae+eucraniini.html

https://vtechworks.lib.vt.edu/bitstream/handle/10919/50620/Wu_S_D_2013.pdf?sequence=1

http://en.cnki.com.cn/Article_en/CJFDTOTAL-SWXZ200505014.htm

http://www.sciencedirect.com/science/article/pii/S1049964485710365

http://www.insect.org.cn/EN/abstract/abstract9677.shtml

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0114238

http://www.nhm.ac.uk/research-curation/scientific-resources/taxonomy-systematics/myiasis-larvae/

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0121504

http://www.nature.com/articles/srep26652

http://en.cnki.com.cn/Article_en/CJFDTOTAL-KCXB200909005.htm

http://link.springer.com/article/10.1007/s00253-009-1971-2

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0121504

http://link.springer.com/article/10.1007/s11274-013-1470-6

https://www.ars.usda.gov/ARSUserFiles/12754100/PyraloideaKey.pdf

http://edoc.unibas.ch/415/1/DissB_7513.pdf

Hoping this will be helpful

Regards

Prof. Houda Kawas

Chapter Keys for Identification of Immature Insects

Also

Very useful references Dr Houda!